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Bringing the science of badger culling up to date

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The original Randomised Badger Culling Trial (RBCT) analysis

The Government’s English badger cull policy since 2011 has rested all but entirely on the RBCT analyses, the first of which was Donnelly et al (2006). It is the science that DEFRA has used to create intensive, supplementary and Low Risk Area (LRA) policy and in court to defend their decisions to ‘experiment’ with badger culling. The claim from this work was that badger culling along similar lines can reduce bovine TB cattle herd breakdowns by around 16% per year; dozens of subsequent studies used in policy and to inform economic and operational models  on which the badger cull policy hangs, were heavily derived from and dependent on the RBCT and most of these remain in place in 2025.

A challenge to the RBCT analysis

First preprinted in December 2022, a comprehensive re-evaluation of the RBCT was published in July 2024 in Nature Scientific Reports (Torgerson et al 2024). The new study re-examined data from the RBCT proactive culling experiment, using the most epidemiologically appropriate range of statistical models, in accordance with the experiments design. It concluded that most standard analytical options show no evidence to support an effect of badger culling on bovine TB in cattle. The statistical model selected for use in the original study in 2006 was one of the few models that did show an effect from badger culling. However, various criteria suggest that the original model was not an optimal model compared to other analytical options then available; the most likely explanation for the claimed culling benefit was that the chosen model ‘overfitted’ the data and used a non-standard method to control for disease exposure. This gave the model a poor predictive value, i.e. it was not useful in predicting the results of badger culling. The more appropriate models in the Torgerson study strongly suggest that badger culling did not bring about the disease reduction reported. Further, inclusion of ‘all reactors’ to the tuberculin test showed no effect of culling irrespective of the model used.

Shortly after, on 21st August  2024, and as a response to Torgerson et al 2024, two of the authors of the original analysis of the RBCT from 2006 (together with a third student author) published two new papers in the Royal Society Open Science journal (Mills et al 2024a&b) using large amounts of the Torgerson preprinted models and doubling down on their original conclusions saying they were ‘robust’. On 16th September 2024, a ‘Comment’ response to the new Mills et al. 2024 papers was submitted to the RSOS: “Randomised Badger Culling Trial—no effects of widespread badger culling on tuberculosis in cattle: comment on Mills, Woodroffe and Donnelly (2024a, 2024b), (Torgerson et al 2025). After a delay of eight months, this was accepted (with minor modifications) on April 23rd 2025 and published on 11 June. This new publication further exposed the flaws of the original RBCT analyses and the more recent attempt to defend it (Donnelly et al 2006 and Mills et al 2024a&b). The findings were endorsed by a senior biostatistician who described key aspects of analytical choices in Mills et al. and the 2006 paper as “naive at best” (Brewer 2025). A letter in Vet Record from October (Torgerson 2025) states that “A request has been sent to retract the 2006 RBCT proactive culling paper, as the results have been shown to be untenable. In my view papers published since 2006 that are reliant on the veracity of the RBCT analysis and results also need to be corrected or retracted.“

The latest Godfray review update of the science of bovine TB (Godfray et al 2025) published in September 2025 agreed that the Torgerson et al. 2024 analysis is the more ’natural’ way to analyse the RBCT data, but beyond its brief to review scientific material published since 2018, decided to undertake its own analysis. This used a binomial rather than Poisson approach to conclude a badger culling benefit from the RBCT data, but at a much lower level of significance than previously presented – it was transformed from ‘weak’ not ‘strong’. Thus agreeing with Torgerson and destroying evidence for the perturbation effect hypothesis.

However, the Godfray/Silverman RBCT model in the review update has additional flaws, and it is not based on the complete data set; it did not include the important ‘time at risk’ variable.  As a result, its binomial model follows a similar pathway as the 2006 analysis. When time at risk is included with the appropriate adjustments, the results suggest no effect of culling. In reality the Godfray/Silverman work pulls down the Donnelly 2006 analysis and then itself, completely undermining the RBCT and a vast volume of subsequent science and policy based upon it. A preprint outlining the various problems with the new model was posted in October 2025 (Torgerson 2025).

Godfray’s review update concluded that the RBCT now provides “limited (if any) insights into the design and likely value of including culling in a control programme”, despite the basis and inference it provides for a large number of later studies, including whole genome sequencing (WGS), which it now looks to for “valuable new information about the risk of infection from badgers”. The huge importance of the loss of Donnelly et al (2006) and its associated papers as plausible science is not mentioned.

APHA analysis of the industry-led badger culls

Brunton et al (2017) and Downs et al (2019) analysed data from the first two, and then up to four years of culling respectively, but for only 2 and 3 cull areas respectively. Large benefits from culling were claimed, but neither had sufficient data to draw robust conclusions and both were heavily caveated. Both repeated the statistical flaws of the Donnelly et al. 2006 analysis and Donnelly was a co-author. These papers too are now invalidated by the recent appraisals.

In March 2022, a new study (Langton et al 2022) in Veterinary Record journal, looked at data from the first six years of badger culling. Firstly, it looked at herd breakdown incidence and prevalence of cattle bTB in areas that had undergone a badger cull and compared them with the data from areas that had not had culling. This was done over a seven-year period 2013-2019, so before and after culling was rolled out in 2016; hence it was a study of the first three years of culling. Multiple statistical models checked the data on herd breakdowns over time and failed to find any association between badger culling and either the rate of incidence or prevalence of bovine TB in cattle herds.

Secondly, the 2022 paper looked at the trends over time of disease rates for the same period. Data suggests that the cattle-based testing and movement control measures, including annual tuberculin testing from 2010, were most likely responsible for the slowing, levelling, peaking and decrease in bovine TB in cattle in the High Risk Area (HRA) of England during the study period, in most areas well before badger culling was rolled out.

Despite being rigorously peer-reviewed (by 4 peer-reviewers, including Vet Records in-house statistician), the paper and its authors were attacked by Defra in the media and on their blog, and its findings were not accepted. The Chief Veterinary Officer and Defra’s Chief Scientific Advisor published a rebuttal letter alongside Langton et al, claiming their data showed that badger culling was working. Six weeks later Defra admitted that their data was wrong and published a new graph of data. They maintained, however, that this did not change their overall conclusions about the new paper, and did not respond to the rebuttal arguments that the authors put forward in the 2nd April 2022 issue of the journal Veterinary Record. Criticisms by government suggested that greater declines had happened in culled areas, but the confidence intervals were too large to show any clear effect. No analysis was offered by Defra to back up the claim who attacked the papers authors, the peer reviewers and the journal. Subsequent ‘Freedom of Information’ requests released emails showing that Defra had sought to block the paper after it had been accepted.

No further comment was made from Defra until (at the Request of Godfray/Silverman) the posting of a preprint, Robertson (2025), that used the disputed analyses (from Donnelly 2006 & Birch 2024 see below) to generate data simulations, to claim that Langton et al may not have detected a disease benefit if one had existed. This used a lower estimated change of 2.8% reported in the first years of culling by RBCT model outputs, rather than the substantial claimed benefits in the more recent APHA papers. The arguments put forward by Robertson are addressed in a brief preprint by Langton (2025) demonstrating that a normal approach to checking data variation shows the Robertson claims are highly likely to be spurious.

The February 2024 paper by Defra staff (Birch et al.) was used to justify further culling proposals in the March 2024 Defra ‘targeted culling’ consultation, and implied, using convoluted wording and without any evidence, that the culling programme thus far had been successful. This was repeated heavily by the Minister and trade press, creating a mass mis-information process that was countered by the incoming Labour government that called culling ‘ineffective’. Authors of Birch twice acknowledge (on careful reading) that while they may speculate, the overall changes in disease levels cannot be attributed to badger culling: all disease measures implemented, including new additional and extensive testing, were analysed together with no control. Claims of badger cull benefit from this analysis are further undermined by its under-declaration of the use of Gamma interferon testing; Birch claims this wasn’t being carried out during the first two years of culling, but government data suggests otherwise (see here and here). There was no comparison of culled and unculled areas, despite the Godfray review update suggesting that there was. Birch cannot attribute recorded benefit to badger culling and provides no insight at all.

Writing in a preamble to Badger Trust’s report ‘Tackling Bovine TB Together’, key badger ecologist and original RBCT scientist Professor David Macdonald writes that the authors of Birch “… do not claim to have measured the consequences of badger culling, and indeed they have not”, and, “there is still no clearcut answer regarding the impact of this approach to badger culling on controlling bTB in cattle or, more broadly, whether it’s worth it.”

A flawed method to identify the source of infection

Badger culls have previously been justified using the guess-based ‘Risk Pathways’ approach of the Animal Plant and Health Agency (APHA). This system sees farm vets invited to speculate on the likely origin of infection. If they are unable to link it to a previous cattle infection (they only look back four years), they often tick the box that blames an environmental source, by default badgers. No evidence is required. However, a study in TB-Free Switzerland of a single-source new outbreak found suggested persistence of bovine TB in a dairy herd for nearly fifteen years without detection (Ghielmetti et al 2017). Further, it is now accepted that the standard SICCT test, at standard interpretation, has an average herd sensitivity of around 50%, thus missing up to half of infected herds and several infected animals per herd; hence disease is remaining undetected in around 20% of herds. The lack of scientific evidence supporting the APHA approach in the Low Risk Areas to identifying the source of disease is discussed in the independent report Griffiths et al (2023).

A new way to blame badgers – Whole Genome Sequencing (WGS)

The Godfray review update (2025) strongly endorses the use of WGS, saying; “…recently introduced  techniques, especially WGS, have provided valuable new information about the risk of infection  from badgers, consistent with, but significantly extending, the original inference from the RBCT that badgers do present some risk to cattle”.

However, this is a broad and unqualified statement . While WGS studies (there are  around nineteen of them) generally report some evidence that a particular strain has been found, time-dated, in a sampled badger and a sampled cow, they do not accurately report the frequency with which transmission occurred, nor the exact route, which may even be via another organism. WGS’s capacity to deliver conclusive findings in the exact route of transfer of pathogens between hosts is still in its infancy and constrained by accuracy in controlling and sampling multi-host situations in varied commercial settings over relatively long periods of space and time. Outcomes are dependent on choices made within complex models that are often not published, are speculative and should be considered with utmost caution. The results reported by WGS studies are not consistent; conclusions reported differ widely. The Godfray review update listed some of the findings but did not do any critical evaluation of them; this remains absent. There is a risk that the Godfray review may repeat the same failings as the Godfray restatement of RBCT findings in 2013, published by the Royal Society,  by not checking the veracity of publications.

Some of the WGS studies have used results from the original RBCT analyses in their modelling, which subsequent to successful challenge, should now be seen as scientifically unsupported. Many use the RBCT’s inference of the supposed benefit of badger culling as inference of a likely transmission route from badger to cow and likewise are now unsound.

Are ‘unconfirmed’ reactors infected with bovine TB?

The Godfray review in 2025 was charged with ruling on the matter of whether cattle which react to a lesser extent to the SICCT test, but where they pass subsequent tests should be categorised as infected. This distinction is of great significance because when ‘all’ data (confirmed and unconfirmed) are included in the RBCT analyses, no badger culling benefit is found (in Donnelly et al 2006 or Torgerson et al 2024). Also, because until recently, stock known to be infected (Officially Btb-Free Suspended (OTF-S)) could be kept in the herd and traded in England.

Importantly, APHA epidemiological monitoring of bTB incidence currently focusses on confirmed reactor data (Officially BTB-Free Withdrawn (OTFW)) to report on the progress of disease control. Inclusion of unconfirmed animals in the data (prevalence) indicates that the disease remains largely unchanged after 12 years of Badger Control Policy (BCP) (Langton and Torgerson 2025). An explainer for the jargon around this issue is available here.

The Godfray update did not determine this issue however, saying only; “Detailed research is needed to allow these questions to be addressed systematically in ways that achieve a  consensus among the various stakeholders.

Policy implications for badger culling are considered here.

Westminster Hall debate on ending Badger Culling, 13 October 2025

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The Westminster Hall debate of the Protect the Wild petition, held on 13th October, was a significant improvement on previous badger cull debates.  The majority of voices spoke earnestly about a wish to stop badger culling and address TB testing failures as soon as possible. There wasn’t a repeat of the nonsense we have previously seen;  “too many badgers” and “killing hedgehogs, bees and ground nesting birds”. And the Minister Angela Eagle concluded by committing to ending the badger cull by the end of this Parliament (2029), possibly hinting at terminating remaining licenses to bring all culling to a conclusion in 2026.

But the debate remained very much ‘behind the curve’. MP’s referenced scientific studies that have now been shown to have used implausible statistical methods (Brunton et al 2017 and Downs et al. 2019), or have implied inaccurate conclusions from government analyses (Birch et al. 2024). Several drew their facts from the latest “Bovine TB strategy review update” by the Godfray review panel, but as Badger Crowd has repeatedly pointed out, the scientists who worked on this document are largely the same scientists who have supported the now impugned previous work that claimed badger culling  could be effective. They are, quite naturally, strongly resistant to accepting that this view may be wrong; they are simply not independent, as claimed. MP’s are looking to the Godfray Review for inference, but they are not getting a balanced summary of recently corrected science.

The narrative being put out by some MP’s was that the scientific consensus remains that badgers give bTB to cattle at a rate that necessitates badger intervention. Others said it was all over exaggerated and the issue remains uncertain at best. With the results of the RBCT no longer able to support a benefit from badger culling, the implied transmission from badgers to cattle reverts to being an un-evidenced idea. DEFRA has been unable to show that the culls since 2013 have produced a disease benefit, although they claim that it is ‘likely’. This is presumably based on their own confirmation bias, based on out of date studies. They are hanging their hat on Whole Genome Sequencing (WGS) to keep blaming badgers, and Angela Eagle, reading the Defra script given to her, said that this could provide a definitive answer. However, with methods available at the moment, WGS is very much open to interpretation. It provides a range of outcomes that greatly vary and rely on a range of choices and decisions that are not always readily quantifiable and checkable. Often their inference is once again taken from the RBCT, that badgers are responsible for a significant amount of disease in cattle, but this is now unlikely or uncertain at best.

No MPs mentioned specifically the 2024 Torgerson et al reanalysis of the RBCT, or its subsequent defense from the original RBCT scientists (Torgerson et al 2025), which definitively show that the RBCT could show no disease benefit  from its results. The hastily put together RBCT analysis annexed at the end of the recent Godfray review claiming to show a smaller badger cull benefit at much lower level of significance has significant statistical problems, and is currently being investigated.

So while we are encouraged that the language and thrust of the WH debate is better than it has been previously, clearly the implications of recently published science have not yet filtered through to MP’s, and perhaps this will take a bit more time. The questionable briefing notes for the debate (generated from government documents)  are a clue as to why this is the case. The same civil servants who served the Conservative government with their strong ambitions to cull badgers are now serving a Labour government, who is aiming to stop culling badgers. But these are people who are invested in their previous views, with published scientific papers and reputations to protect. Do we have to wait for a wave of early retirements before we start to see the objective view of the science that the issue deserves?

Are both sides of the badger cull argument ‘mining the data’?

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It has been claimed that the disagreement about the Randomised Badger Culling Trials (RBCT), and what that central study tells us about whether badger culling can reduce bovine TB breakdowns in cattle, is a result of ‘data mining’ from both sides. That is, both sides are selecting the methods of analysis that give them the result they want. Is this a true representation of the current situation which sees different analyses giving opposite results? Or is the claim just a bit of a smokescreen?

Basically, there are two models that are used to claim that badger culling produces a disease control benefit to cattle;

1. Donnelly et al 2006 produced the only Poisson model (there are many others available) that says badger culling ‘worked’ with around a 20% benefit (P 0.005%).

2. In the recent Godfray review of evidence, Bernard Silverman downgraded the Donnelly model and produced the only binomial model (of 4) that indicates badger culling had an effect, with around a 17% benefit (P 0.05%). A similar effect but at a much weaker level.

However, the Donnelly model did not correctly adjust the data for the number of herds in each trial area, nor the ‘time at risk’. And the recent Silverman analysis did not correctly adjust for ‘time at risk’. So neither analysis correctly adjusts for exposure to disease during the experiment.

Professor Torgerson’s reanalysis of the RBCT data in 2024, published In Nature Scientific Reports, reviewed a wider range of analyses in accordance with veterinary principles, the most appropriate/best fitting of which (based on model rating criteria and parsimony) suggested the superior models showed no benefit from badger culling.

If there was a convincing effect from what is a relatively small amount of data it would be visible in most or all of the analyses undertaken. Two selected models that have not been properly adjusted for important variables compare poorly to stronger ones that don’t. Claiming a benefit from badger culling from the RBCT is not verifiable because the claimed effect is not consistent. The correctly specified models consistently show badger culling produces no visible effect on disease in cattle.

For those wishing to read more about the recent reanalyses of the RBCT, our post on the 11th June Royal Society Open Science paper shows how the original 2006 analysis and subsequent attempts to support it were flawed and even ‘naive’, and our post from September 17th outlines statistical issues with new analyses in the recent Godfray review.

So the answer is that there is no data mining going on, at least not by those seeking to independently check the data. Just a thorough review of the best statistical way to understand the simple data involved, using the kind of approaches that the original scientists implied that they would use.

Godfray Review 2025: Defra Revision? Correction? Or just further scientific howlers?

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On Friday 26th September, Defra changed the “Bovine TB strategy review update” but simply made things worse by adding another layer of confusion.

The correction of reported Information Criteria as now shown in the Godfray Review

An error was reported as “a revision to a line of code”. In the document itself, the change is referred to as a ‘cut and paste error.’ Red text in a box next to the correction (see above) suggests that ‘The rest of the analysis and interpretation is unaffected’.

The replacement red numbers, now show the  outputs from their 4 models described, but this time the difference between models 3 and 4 is insignificant. To put it in technical terms, a delta (difference) AICc of 0–2 suggests both models have similar support from the data.

However, far from the analysis and interpretation being unaffected as they suggest, the revision does have serious implications for the inferences drawn. The ‘update’ is actually a correction due to the wrong results being inserted into their models in Annex 4. The results reported as AICc (Akaike Information Criterion) were in fact the results from Baysian analysis (BIC) (which they did not report on).

However, BIC is not the correct IC for model selection, due to the small number of data points and large number of coefficients to estimate. The small sample size equivalent (was this really not tried?) would be appropriate (BICc), especially for logistic regression. Applying BICc favours a model which suggests that the incidence of herd breakdowns is independent of culling (i.e. culling produces no effect).

If AICc is used for model selection, a model suggesting a weak effect of culling is only slightly favoured, model 3: 173.58 vs model 4: 173.87. This difference is too small to draw any inference from; it is effectively a toss-up between the two models. The incorrectly reported IC results showed a bigger difference: model 3:151.58 vs model 4:159.38). It is this greater significant difference, which is what the peer-reviewers seem to have picked up on. Hence the big question, what were the peer reviewers sent? And given that one or both reviewer assumed the code was right, were they commenting on the wrong results?

Apparently Defra have been asked this all-important  question and an answer is pending. Maybe they don’t know and need to ask?  The answer could alter the Chapter 6 discussion hugely. A very large number of people are interested to find out who knew what and when.

The Information Criteria as originally presented in the Godfray review

One might pose the question “did the Godfray group try the small sample size BICc?” Given that they obviously tried BIC (as that is the output they incorrectly reported), the correct form of BIC would be the small sample size correction as there are only 20 data points. Interestingly, when BICc is applied, model 4 (without badger culling at 196.00) is favoured over model 3 (with badger culling at 200.96). I.e. badger culling has no effect.

However, notwithstanding all this incredible muddle,  it would have been more appropriate to select the most favourable model of a series of over-dispersed models, using the quasi version of AICc, which is QAICc, especially as the quasibinomial model was subsequently used for statistical inference.

When the QAICc is applied to their models, the results strongly favour a model which again suggests bTB incidence in cattle is independent of badger culling (i.e. culling produces no effect).

A pre-print outlining some of the problems with the new analysis is available here.

Reasonable people can disagree….

When dealing with the recent academic publications on the RBCT, (which have been reported on here), and which arrive at different conclusions, the Godfray review has stated at para 6.LXX:

“…reasonable people can disagree about the best way to analyse complex data such as these.”

That is an interesting response to the current differing views. A short article entitled “When Can Reasonable People Disagree?” is quite insightful on this. We borrow a couple of apposite quotes below:

“To say that “reasonable people can disagree” can encourage suspension of judgment in response to important matters of personal and social concern.”

“There is a related tendency to use the expression “reasonable people can disagree” to create an equivalence when it comes to conflicting beliefs that large groups of people hold. A common perception exists that if a large enough group of people believes something, it has met the litmus test for being a “reasonable’ belief and the people involved “reasonable people.” This is a familiar critical thinking error. The fact that a large group of people believes something does not provide us with a compelling reason for thinking it is true.”

“Respect for persons might require engaged listening. It might require careful consideration. It does not require treating weak evidence as if it is strong nor does it require treating unsound arguments as if they are sound. Far from being kind, we are actually doing one another an injustice when we engage one another as if all arguments are equally compelling.”

The point is, and it is a  point made by Prof mark Brewer earlier this year in his review of Torgerson et al 2025, it is more a question of can reasonable people agree?  And the answer to that appears to be not yet. But there  needs to be conversation. So far Defra has refused to have that conversation. Will that continue or does it have to wait until there is an inquiry into the crisis?

In any event, this muddle is so bad that the Godfray review will need to be rewritten. That is unavoidable now. The mistakes are too obvious, too profound and too important to remain as a part of the narrative.

While there is a ‘it doesn’t matter anyway’ type sentence to cover up any exposure, it is quite clear that it really does matter. The mistakes alter everything, including the economic forecast on badger culling benefit.  

Its time for Defra to change the way they do business.

 

 

Vacuous  vaccination?

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Badger blame folly continues undercover

Have you noticed how quiet the NFU have become over badger culling since Labour came to power?  Why could this be?

Steve Reed & badger

Badger Politics

In 2024 there was an agreement between the NFU and Labour not to make an issue of badger culling during a general election year. This was on the basis that Labour would ‘honour’ existing licences if they came into power – thinking that might be after the 2024 cull was over. But the election was called early by PM Rishi Sunak, and the surge in the Reform party popularity split the Tory vote and resulted in a Labour landslide. Labour’s undertakings meant they would go on to kill around 17,000 badgers in 2024.

Intensive culling programmes get go-ahead to continue to give ‘clarity’ to farmers

The first news from the new Secretary of State for Environment, Food and Rural Affairs Steve Reed in 2024 was confirmation of the agreement with NFU that the current  badger culling programmes set to end in January 2026 would continue until then to give the farmers ‘clarity’. This decision went against advice from Natural England, who preferred the introduction of badger vaccination to seek a disease control benefit. But this advice was itself flawed, with growing evidence that there is unlikely to be any disease benefit from culling, and benefit from vaccination is entirely speculative. Natural England simply failed to properly consider evidence that  badger culling has no likely benefit, and simply cherry-picked the evidence they wanted to get past the task. ‘Freedom of Information’ now shows us that they also relied on unchecked manuscripts, claiming naively that badger culling had robust effects.

The death of targeted culling?

Around six weeks after getting into office, Labour moved to scrap the NFU/Defra pre-election ambition to get mass (targeted) culling going (along the lines of LRA hotspot culling) in the HRA and Edge Areas. This targeted culling, developed under Rishi Sunak’s tenure as PM, was in defiance of the 2020 ‘Next Steps’ Boris/Carrie Johnson/Zac Goldsmith policy which was to phase out badger culling. Phase it out “other than in exceptional circumstances”, that is. This caveat was the toe-hold for future culling that pro-cull interests in the civil service managed to keep on the job-sheet, to fight back with, now that Environment Secretary George Eustice had been overruled.

But a new Low-Risk Area cull was then given the go-ahead

Under strong NFU pressure, Labour still gave in to a new Low Risk Area cull in Cumbria. Was this an attempt to appease their industry masters by keeping new culling going, aware of  the long planned unpopular Farm Inheritance Tax news that was  about to be released? Did Labour use badger culling to indulge the farmers, in an attempt to distract from the freight train coming?

New Minister – new policy? Or just more of the same DEFRA dogma?

Excerpt from the Labour Manifesto, 2024

The problem for DEFRA  was how to balance Labour’s manifesto position that culling is ‘ineffective’, with the claims made by the Conservative Government politicians and their usual external contractors, of badger culling ‘working’; see the Downs et al 2019 and Birch et al 2024 papers. These publications have a pick-and-mix of confirmation bias, repeat of previous flawed analytical methods, stretched arguments, unevidenced speculation, confused presentation, key omissions and complex caveats. Of course many of the Government scientists who produced science that has facilitated badger culling for so many years are still in post. So how do they do a volte-face, and suddenly disagree with their own back catalogue of dubious science? Nobody likes to be wrong, and nobody is owning up to it so far. (see here for latest science update).

The Godfray Review

Another review of bovine TB control science (published since 2018) was commissioned secretly in 2024, and announced publicly in early 2025. The ‘Godfray’ review panel  is soon to deliver its report, but it is hopelessly stacked with vested interest. Some panel members have a long history in badger cull science, with Oxford University’s Charles Godfray, together with James Wood from Cambridge University, publishing a re-statement in 2013 (of now impugned conclusions), which was needed to greenlight badger culling. Surely the most positive spin that the review can come up with is that Government post-2013 cull outcome research is inconclusive? Pro-cull cheer-leader James Wood said as much recently on Farming Today. But he couldn’t resist repeating his long held personal view that badger culling helps TB control.

The Westminster Hall Debate – waiting for a date

A large number of pro-badger killing MP’s were purged by the general election. It was almost as if their support of badger culling was proportional to the rejection of them by the voting electorate – dozens of them. So no longer will Richard Drax, Bill Wiggins, Robert Goodwill, Steve Double and many others  be able to drivel on at Westminster Hall with anecdotal nonsense. Might the next one, resulting from the Protect the Wild petition, be fact-based perhaps? A date is yet to be allocated.

Back to the NFU

NFU get vaccination contract

So back to the question – why have the NFU been so quiet?  Well perhaps they still hope to be granted their wish to keep killing badgers. DEFRA has now funded a badger vaccination project in Cornwall. The NFU have been awarded the contract to undertake the work, working with the Institute of Zoology.

The new  £1.4 Million project hopes to train farmers to swap bullets for syringes (think banned RSPCA poster) in a so-far rather loosely described project to vaccinate badgers in the county for three years (2026-28) and compare it with somewhere else – either unvaccinated areas in the county or elsewhere. Details at present  are scant, but have been requested. Pre-experiment plans are vital for the delivery of useful results in a verifiable way and should be open to scrutiny, especially those concerning statistical approach.

Vaccinate or Exterminate. Will DEFRA’s new approach ignite further controversy?

But why would the NFU take the money to do something they are supposed to be inherently against, according to farm research (see here)? The reason could be, either with or without DEFRA Minister Zeichner’s permission, that NFU have been preparing ‘under the radar’ with Defra/APHA to head towards ‘Test Vaccinate Remove’  (TVR ) – where farmers learn to trap badgers, test with a dubious trap-side DPP test (see here) that in Wales was a disaster (see here), and cull the badgers that test-positive.

Is this the dirty secret about badgers that is keeping the NFU quiet?

Perhaps Godfray and his panel of not-very-impartial reviewers, (see here) who  have been asked to lean towards Labour’s preference for non-lethal badger intervention options, would be expected to leave the door ever so slightly ajar, hence open to TVR, simply by saying that badgers remain a TB risk to cattle.

This would satisfy the Defra/Civil Service ambition of bringing one single approach to disease control to three UK countries; Wales (possible new Reform/Welsh Nationalist government pro-cull wish in 2026), NI (UFU currently frothing at the mouth to cull) and England.  This may be the fantasy result for Defra, but it would be the grotesque, disastrous result of using selective and plain-wrong science. It would be an extension of the UKs failure to tackle livestock disease effectively over the last 25 years (see National Audit Commision report here).

Will the NGO’s want to help the NFU vaccinate badgers?

It is interesting to note that the NGO’s are becoming less keen on badger vaccination, including the Wildlife Trust and Badger Trust. Partly because most vaccination teams have been frozen out of funding for this work that they have undertaken to protect badgers from bTB. Government has been aiming to capture and control the whereabouts of badger setts and badger vaccination for some time (see here) and it is handy for them if the NGOs stand aside or assist.  NGO’s do hold important badger sett information that Defra would be keen to get hold of for potential future culling – when the NFU have demonstrated that badger vaccination either doesn’t work or somehow isn’t enough – cover for another 5 years of ineffective cattle testing and compensation?

So there are a few possible reasons that the NFU are so quiet. It could of course be that they recognise that the failed cattle testing system with inadequate use of tuberculin and gamma testing, imposed by Defra, has destroyed farm interests for a generation while the food wholesalers continue to have uninterrupted supply. But they won’t stay quiet about that for ever will they? Why would they do that?

What did The Royal Society peer-reviewer say about the new Torgerson et al (2025) paper?

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Professor Paul Torgerson


The peer-reviewer of the new scientific paper, Torgerson et al 2025,  published on June 11th is the Director of Biomathematics and Statistics Scotland (BIOSS). The paper is concerned with analysis of the Ranomised Badger Culling Trial (RBCT). Below, you can see the text of the review together with the authors responses, as addressed to the editor.  Also highlighted (bold italics) are a few points that seem particularly important & difficult to disagree with, even if you don’t understand statistics. It should be noted that the two reviewers of the Mills et al. (2024) papers that Torgerson et al. is rebutting, declined to submit a review of the new Torgerson paper. In other words, they praised the two Mills et al papers, recommended them for acceptance, but declined the opportunity to defend their decision by explaining their thinking on Torgerson et al (2024 & 2025). They remain anonymous, which is interesting from an integrity perspective.

These communications are available from a link (Review History) on the online paper.

Torgerson: The reviewer has made a number of comments. We have addressed these where necessary and made some amendments to the text. We would also like to thank the reviewer for these helpful comments which we hope have improved our manuscript.

Reviewer: Comment. Overall it seems there is strong disagreement over competing data analyses on what is already a highly contentious issue, which has significant implications in terms of ecology and agriculture. I have been asked to comment on one small part of the ongoing discussion, which I will do – however, my overall, strongest recommendation is that, given the importance of the underlying issue (both scientifically and politically) that a proper investigation be conducted to establish an agreed position involving all parties. A continuing to-and-fro among different sets of authors – each, I am sure, well-meaning in their own ways – serves little purpose, and there are better, more efficient and effective ways of resolving disagreements than in the pages of an academic journal.

Torgerson: The underlying issue (mass culling of largely healthy badgers across much of England and in Ireland) is the result of the original analysis by Donnelly et al, first published in Nature in 2006 and papers derived from that, and subsequent analyses. Although the merit of the analysis has been questioned, only by having alternative data analyses published in peer reviewed journals is it possible for the UK Governments to consider amending the policy. Nevertheless, we have contacted Donnelly et al previously in an attempt to meet and to find common ground, but our attempts were rebuffed. In order to give the reader a clear idea of the applied implications of both our re-evaluation and the peer review comments, we have added some text to the conclusions: “Accordingly a very substantial number of publications that rest extensively or completely on RBCT statistical analyses may require major qualification or retraction. The justification for lethal control of badgers to-date appears to have been based upon basic statistical oversight.” Also there is a reproducibility crisis in science. Therefore it is important for these issues to be published as we believe they provide an exemplar of a major driver to the reproducibility crisis and misdirection of disease epidemic management.

Badger Crowd Comment: A scientific seminar and evening presentation on the work of Paul Torgerson and his team (then a pre-print) was organised in Oxford in November 2024 in order to allow debate with the RBCT scientists. All declined the invitation. DEFRA and APHA sent no representatives. Natural England sent one staff member but gave no feedback. Badger Crowd very much welcomes the reviewers suggestion to hold a “proper investigation…to establish an agreed position involving all parties.”

Reviewer: Comment 1) Section 2.1. I agree with the authors of the current contribution here that use of an offset here is likely a requirement, and that the comments from the Mills et al. (4) are naïve at best – it isn’t helpful to think of an offset as equivalent to setting a regression coefficient to 1.0, as of course the issue is that this is a log-linear scale and the point is that (under the Poisson) we assume proportional rates. I agree that it does not seem to make sense that the herd breakdowns vary only very slightly (the parameter value of 0.04) with the number of herds, although I would caution here only that it is possible some other variable/term in the model might be related to the number of herds, hence suppressing the parameter value (when including number of herds as a regression term rather than as an offset) owing to collinearity.

Torgerson: This is quite possible, and the collinearity is likely to be between the co variates of “triplet” and “baseline herds at risk”. Hence the motivation to explore the results of models where triplet was removed (which always resulted in a considerable reduction in AICc). Although it is not clear if the reviewer required a response to this statement, we have inserted the following text into the manuscript “The removal of “triplet” may remove any hidden effects possibly due to collinearity with number of herds, as well as substantially reducing the number of covariates and hence largely eliminate the issue of over fitting.”

Reviewer: Comment 2) I have personally written (Brewer et al, 2016 – https://doi.org/10.1111/2041-210X.12541 ) about the dangers of relying on the theoretical distinctions between AIC/AICc and BIC, so it should be no surprise that I share the current authors’ suspicions on the preference expressed in Mills et al. (4) for BIC. Also, why are the AICc values for Models 1 and 3 so much higher than the null model in Table 1? Is this just a feature of the small-sample correction? Otherwise I would not expect this at all (if I’m understand what the null model is, correctly); in the absence of other explanations here, given the high number of parameters in models 1 and 3 I would suspect poor model fitting with inflated variances due to collinearity. So, I agree with the current authors here, on the basis of the evidence in front of me (Sections 2.2+2.3, Table 1, supplementary material).

Torgerson: This issue is well taken. This was part of our arguments. Although perhaps not completely clear. We have edited the relevant text which now reads “Brewer et al (16) have written about the dangers or relying on theoretical distinctions between AIC/AICc and BIC. Nevertheless, Mills et al. (4,5) state “…a wide array of statistical techniques and study periods allows us to make robust conclusions regarding the effects of proactive badger culling which are informed by consistent scientific evidence from trial data, irrespective of which approach to statistical inference is taken.” This is demonstrably untrue. The analysis of “confirmed breakdowns” (OTFW) show that results are highly dependent on the approach to statistical inference and information criteria used. However, absence of any cull effect on the incidence of bTB, when total breakdowns are considered, is robust, irrespective of statistical method.”

Reviewer: Comment 3) The discussion on Bayesian models claims that the authors of Mills et al. (4) made coding errors. I do feel that then Mills et al. should be able to examine and (if relevant) correct these errors, and formally issue a correction in the pages of the journal. Otherwise, I don’t feel I have sufficient information to comment further here.

Torgerson:  Here the reader needs to refer to both the coding on GitHub, which is where Mills et al have made their statistical code available and the code we have given in the supplementary material. We give an example here.
In Mills et al, they claimed an offset was used with the following R code:
rs1aB←stan_glm.nb(Incidence~Treatment+log(hdyrsrisk),+log(Hist3yr), offset = log(hdyrsrisk), prior_intercept=normal(0,10), prior=normal(0,10), data = rbctconf, refresh=0)
Here you will note (in red) that log(hdyrsrisk) appears twice in the code, both as an explanatory variable and an offset. The effect of this is to shift the parameters of log(hrdyrsrisk) by a value of 1, whilst other parameter values remain unchanged, thus effectively having no offset.
The correct code if a parameter value is to be fixed as an offset is:
rs1aB<-stan_glm.nb(Incidence~Treatment+log(Hist3yr), offset = log(hdyrsrisk), prior_intercept=normal(0,10), prior=normal(0,10), data = rbctconf, refresh=0) or alternatively:
 rs1aB<-stan_glm.nb(Incidence~Treatment+offset(log(hdyrsrisk))+log(Hist3yr), prior_intercept=normal(0,10), prior=normal(0,10), data = rbctconf, refresh=0)
We refer the reader to our supplementary material where it is fully explained together with the other errors in the code of Mills et al.

Reviewer: I agree with the current authors’ concerns on the statistical audit. I would go so far as to say that, given the important of the topic of this discussion, any audit should be carried out openly and transparently.

Torgerson: We have added short text at the end of section 4 “ It is important that trials include an audit that is open and transparent.”

Reviewer: Comment 5) Section 5 on the neighboring area study – again, from what I can see here, I would broadly agree with the concerns of the current authors.

Torgerson: No response required

Reviewer: Comment. 6) To clarify; I have no issue with the modelling of counts, as the use of a Poisson-form log-linear model is, in effect, modelling rates. To be more precise, I would suggest that the problem is not that Mills et al. (4) modelled counts, but that they did not properly scale those counts by use of an appropriate offset – and again, I am saying this on the basis of the evidence of the current work (only).

Torgerson: Here the reviewer appears to be agreeing with our approach by using the offset. But for clarity so readers can see the derivation of the offset (in the Poisson log-linear model) in our previous manuscript where there derivation is explained. Thus we have inserted the text “The mathematical derivation of the offset is explained in our previous manuscript on this issue (3).”

Reviewer: Comment. 7) Finally, I would like to address the quotation from Donnelly (16): “the suggestion of requiring independent replication of specific statistical analyses as a general check before publication seems not merely unnecessary but a misuse of relatively scarce expertise”. The point to me here is not that work should be “replicated” as such, but that work should be verifiable. The authors of Mills et al. (4) have apparently made their work – at least that related to the 2024 journal papers – available openly, and this is the key; openness and transparency are vital. I would even go as far to say that, in such a contentious area as this, it is naïve to imagine that a single analysis by a particular group of scientists should be seen as sufficient.

Torgerson: Yes we agree, which is one of the issues with the original RBCT proactive cull statistical findings published in 2006, which was led by Donnelly: it was a single analysis by a particular group of scientists, and the Mills et al papers are also led by Donnelly et al. We think this is obvious and it should be verifiable. Nevertheless we have modified the text surrounding the quotation of Donnelly (16). It now reads: The position of Donnelly (17) that “the suggestion of requiring independent replication of specific statistical analyses as a general check before publication seems not merely unnecessary but a misuse of relatively scarce expertise”, needs revisiting. This case underlines the need not only for rigorous checks of statistical analysis but also validation of the statistical models and assumptions used within submitted manuscripts to verify them.

Badger Crowd Comment: For the last 6 months, Sir Charles Godfray and his ‘expert’ panel have been reviewing badger cull and bovine TB science published since 2018. Godfray was involved in the RBCT audit, the 2013 restatement of badger cull science and the 2018 science review. In other words, the single analysis (Donnelly 2006) that has supported the badger cull policy is being reviewed by (largely) the same ‘particular’ group of scientists who have been associated with the work for nearly 20 years. Donnelly herself has been ‘recused’, but has been replaced by another Oxford statistician from the same department. There is no outside scrutiny, and there is a case that there has been no “proper investigation ….to establish an agreed position involving all parties” as recommended by the peer reviewer. A proper investigation would be free from conflict of interest. Defra have refused to address this issue over the last six months.

In case you missed the point of all this, the new Torgerson paper shows how for multiple reasons that there is no evidence that culling badger delivers a disease benefit of bovine TB control in cattle herds. The current ‘closed shop’ of science at DEFRA has fallen flat in the past and should not be allowed to continue. They are selecting the scientists and science that they want to suit a civil service agenda and they don’t want to admit that they have been wrong for very many years. It is a flagrant example of policy driven science. And everybody is losing out because of it: the public (because of the enormous costs of policy), the farmers (because it is a policy that can never achieve its aims) and the badgers – because they are being inhumanely killed in huge numbers. 

This intolerable situation cannot be allowed to continue. Badger culling must stop now, and an independent investigation or inquiry must be set up.

Randomised Badger Culling Trial (RBCT) publications update

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Following on from our blog of September 23rd 2024, that reported on the uncertainties around the RBCT analyses, we are pleased to provide an important update. As Jane Dalton writes in The Independent, “Bombshell’ badger cull study review ‘disproves evidence’ used by governments to justify killings.”

A quick reminder of why the RBCT is so important

Government badger cull policy has rested all but entirely on the RBCT analyses. It is the science that DEFRA has used to create policy and in court to defend their decisions to experiment with badger culling. The RBCT claimed badger culling can reduce bovine TB in cattle; very many subsequent studies are heavily derived from it.

Disease benefits that have in recent years been ascribed to badger culling by civil servants and politicians are in reality, far more likely due to implementation of additional cattle measures that were put in place before or at the same time as culling. But Government scientists continue to infer that badger culling has caused a reduction in disease, simply because this is what was “predicted” by the results of the RBCT. its classic confirmation bias.

Below is a chronology of some key RBCT publications.

16th February 2006, “Positive and negative effects of widespread badger culling on tuberculosis in cattle” was published in Nature by Donnelly et al.

10th May 2019, “Badger Culling and Bovine TB in Cattle: A Re Evaluation of Proactive Culling Benefit in the Randomized Badger Culling Trial” was published in the Journal of Dairy and Veterinary Sciences by Tom Langton.

13th December 2022, First version of “Absence of effects of widespread badger culling on tuberculosis in cattle” was posted as a preprint on Research Square by Torgerson et al..

15th July 2024. “Absence of effects of widespread badger culling on tuberculosis in cattle” was published in Nature Scientific Reports by Torgerson et al.

18th August 2024. Interim report on the August 2024 pre-publication response to the July 2024 re-evaluation of evidence and analyses of proactive culling (published in 2006), as a part of the Randomised Badger Culling Trial (RBCT), 1998-2005. Independent pre-publication report on the Mills et al. papers to be published on 21.08.2024.

21st August 2024. “An extensive re-evaluation of evidence and analyses of the Randomised Badger Culling Trial (RBCT) I: Within proactive culling areas”  and “An extensive re-evaluation of evidence and analyses of the Randomised Badger Culling Trial II: In neighbouring areas” were published in Royal Society Open Science by Mills et al..

16th September 2024. A ‘Comment’ response to the new Mills et al. 2024 papers was submitted to the Royal Society Open Science: “Randomised Badger Culling Trial lacks evidence for proactive badger culling effect on tuberculosis in cattle: comment on Mills et al. 2024, Parts I & II” by Torgerson et al.. This was pre-printed with bioRxiv on 20th September.

11th June 2025, ‘Comment’ response to the two new Mills et al. (2024) to the Royal Society Open Science was published: Randomised Badger Culling Trial—no effects of widespread badger culling on tuberculosis in cattle: comment on Mills, Woodroffe and Donnelly (2024a, 2024b),  by Paul Torgerson et al. (2025), Royal Society Open Science.

Inexplicably, the Natural England rationale for licensing the supplementary badger culls in 2025 year did not take the Torgerson et al 2024 preprint into consideration. This is despite considering un-peer reviewed reports this year, and preprints (notably Mills et al 2024) last year.

So although the peer reviewer (Prof M. Brewer, Director of Biomathematics and Statistics Scotland) of Torgerson et al (2025) favours this new evaluation, which concludes that “The justification for lethal control of badgers to date appears to have been based upon basic statistical oversight.”, it was not considered in the cull licensing for 2025. The peer review comments for the new Torgerson et al. Comment paper are available from the online link, and are well worth reading in full.

The justification for badger culling has been shown to be wrong in so many ways. Badger culling must stop immediately, on the basis of scientific evidence.

 

Badger cull analyses were based on “naive” statistics

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The London based Royal Society have published analyses that show how key aspects of methodology of the Randomised Badger Culling Trial (RBCT) published in Nature in 2006 were misdescribed and used implausible analytics. Original statistical appraisal that RBCT authors had claimed was too robust to require checking, was actually fallible, once clearly explained and tested. 

The published Comment paper, addresses two scientific papers, also published in Royal Society Open Science in August 2024 by postdoctoral student Cathal Mills, supervised by Head of Department of Applied Statistics at Oxford University Professor Christl Donnelly, and Professor Rosie Woodroffe of the Institute of Zoology, (Mills et al I & II 2024). This work sought to defend the original analysis of the Randomised Badger Culling Trials (RBCT), (Donnelly et al 2006), which had been challenged by a full research paper published in Nature Scientific Reports in July 2024 (Torgerson et al 2024). A peer reviewer characterized one pivotal choice made in the two Mills et al. papers that tried to uphold the 2006 findings, as ‘naïve at best’.

Professor Paul Torgerson, Head of Epidemiology at the Zurich University Vet School, has led a team to undertake a detailed reanalysis of the original RBCT analysis. Papers derived from RBCT work have been used since 2013 by the Coalition, Conservative and now Labour Governments to justify badger culling. Labour however have called it ineffective, but without detailed explanation and have issued a new cull licence.  Subsequent academic papers have relied heavily on the ‘ground zero’ Donnelly et al. 2006 publication to continue to claim that culling produces a disease benefit in cattle.

In Torgerson et al. (2024), and now also in the newly published and reaffirming Torgerson et al. (2025) “Comment” on the Mills et al (2024) papers, the most statistically and biologically plausible analytical options showed no evidence to support an effect of badger culling on bTB herd incidence. This is consistent with the 2022 analysis (Langton et al 2022) of part of the subsequent industry led badger culls in England (2013-2019), that was unable to detect any disease control benefit.

The “Comment“ also infers that the so-called “perturbation effect hypothesis” no longer holds convincing statistical support. This hypothesis first suggested in the 1970s was of badgers becoming frightened and disturbed (due to the catching and killing of them) consequently dispersing. Then directly or indirectly, badgers were alleged, to be responsible for multiplying the transmission of bTB to somehow cause half of TB cattle herd breakdowns. This mechanism was used to try to explain the claimed effect from the RBCT analysis.

The entrenched understanding of the role of badgers in bTB transmission to cattle over the last 20 years or so is further undermined and finally departs from any empirical support, sending a shockwave through beliefs that have become ingrained in farming, veterinary and Government thinking, where a high level of denial has already been in evidence since uncertainties were raised in 2019.

The implications of the new analyses are enormous, undoing extensive perceptions within multiple stakeholders that badger interventions are fundamental to any policy to control bTB in cattle. Whilst it clear that bTB introduced to wildlife from cattle is shared between wild mammals such as badgers, deer, rats and even domestic cats, exchange between wildlife and cattle has not been shown with sufficient precision in genetic studies to provide confidence. Infected wildlife may result simply from them being ‘spillover’ hosts, where infection dies out once disease is tackled in cattle. New cattle infections continue to occur due to poor testing sensitivity failing to identify disease,  the incorrect designation of herds as ‘TB-Free’ when still infected, and continuous trading of infected calves and yearlings. The ongoing bTB crisis has cost the UK and Ireland an estimated £2 Billion in public payouts and lost productivity over the last 20 years alone, including over £1 Billion in England and Wales since 2013.

In 2024 the DEFRA Minister Daniel Zeichner invited Professor Sir Charles Godfray at Oxford University, to reconvene his 2018 review panel to consider the latest relevant scientific publications. Godfray, was involved in the statistical audit of the original RBCT analysis and in a 2013 report that appraised RBCT badger culling science, and a review in 2018 that recommended badger culling should continue. He has consistently endorsed RBCT statistics and badger culling.

The new paper and reviewer comments are available to read here. 

Quotes from authors

Paul Torgerson, Professor of Veterinary Epidemiology at the Vetsuisse Faculty of the University of Zürich who has led the independent group said:

“The significance of our findings extends to several dozen papers written since 2006 that use the 2006 findings to build a theoretical case that badger interventions are a necessary part of bovine TB control in cattle, when they are not. Much work is now needed to highlight this issue by corrections, retractions and other measures to ensure students and practitioners are no longer misled. Bovine TB control must focus on inadequate TB testing and movement control of cattle where the problems are now well known.”

Tom Langton a nature conservation consultant within the independent group who has studied bovine TB control, has coordinated technical and legal scrutiny over badger culling since 2016. He said:

“The Government challenge to prevent further £1 billion spend over the next decade on more inadequate disease control will require fresh thinking and approaches. The Labour Government has rightly labelled badger culling as ‘ineffective’ and must surely now immediately cancel all badger culling licences while an inquiry is launched, as should Government in the Republic of Ireland, where thousands of mostly healthy badgers are also culled each year with no demonstrable reward. The failures of the TB testing system are now so well established it is unfathomable why prompt government action was not taken last year.”

Badger Culling – where we are now

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In August 2024, Defra announced plans for a ‘refreshed’ bovine TB control badger strategy (here). On 30th January 2025, Defra issued Terms of Reference (here) for their ‘comprehensive new bovine TB review’, a look at ‘new’ science, which will  inform their ‘refreshed’ strategy. This included details of the scientific panel which will be reviewing ‘new’ evidence that has become available since the last review was published in 2018. We have blogged briefly about this here. A new strategy would be the first since that presented in 2014, by Owen Paterson when he was Secretary of State (here). At that time, Patterson said:

“If we do not get on top of the disease we will see a continued increase in the number of herds affected, further geographical spread and a taxpayer bill over the next decade exceeding £1 billion.”

This is exactly what has happened, and what Steve Reed the new Secretary of State could be about to repeat. The outline for the preparation of a new strategy is brief:

  • First Bovine TB strategy in a decade to end badger cull and drive down TB rates to protect farmers livelihoods
  • New holistic approach will ramp up cattle control measures, wildlife monitoring and badger vaccinations
  • Proposals to be co-designed alongside farmers, vets, scientists, and conservationists to beat TB that devastates livestock farmers and wildlife

While Badger Crowd welcomes talk of an ‘end to the badger cull’, the new strategy proposals indicate that this is not guaranteed before the end of the current parliament (2029). This is completely unacceptable. The strategy proposes five more years of badger culling, all without sound scientific basis, and if implemented would result in the total number of culled badgers heading beyond 250,000, with no measurable disease benefit at all.

Holistic measures to ramp up cattle control measures are welcome, along with wildlife monitoring, but proposals for mass badger vaccination to be employed  against bovine TB in cattle are based on unscientific beliefs, uncertainty and guesswork, using methods trialed and rejected in Wales. They are a further betrayal of what was promised and what is urgently needed. They are a scientifically unjustified continuation of the badger blame game, and as misguided as culling in terms of cattle TB control.

The scientific evidence just does not support the continued focus on badgers as a 50% source of bovine TB in cattle, despite the last Government’s claims and  ill-informed media reports. There are no ‘benefits to bank’. Yes, general on-farm hygiene improvements are sensible to prevent disease generally, but the real core need is to change the SICCT gold standard regulations, giving more control to farmers and vets to use a wider range of tests. Re-education of the sector on the science of bovine TB and wildlife, over which they have been misled for many years, is urgently needed.

Who could oppose the statement that “The full strategy will be co-designed with farmers, vets, scientists and conservationists”? But this has been said before, and implemented with secret committees and closed-door briefings, usually with those who are beholden to Defra for grants and favour. It is a breeding ground for vested interests and cover-ups.

Engagement with scientists involved in important peer-reviewed science that questions badger culling (here, here and here) has been prohibited by Defra for at least five years, despite frequent requests for meetings or at least dialogue. Will there be continued resistance to accept the published science that challenges the views of those civil servants at Defra who have been pushing expensive and unethical policy for so long based on decades-old equivocal evidence?  There is an uncomfortable history of bad decision making by those who now need to move along, to allow genuine progress. 

What does the immediate future of
badger culling look like?

Intensive & supplementary culling

The Labour manifesto in 2024 called badger culling ineffective. Sadly, since Labour’s election to power, Steve Reed (SoS for Environment, Food and Rural Affairs (EFRA)), Sue Hayman (Parliamentary Under-Secretary of State for EFRA), and Daniel Zeichner (Minister of State for Food Security and Rural Affairs) have all confirmed that the existing badger cull licences will be ‘honoured’ as they would have been under the previous Conservative administration. But where is the honour in doing the wrong thing?  Culling will continue until January 2026. Leaked figures suggest that 10,769 mostly uninfected badger adults and cubs were killed in the 2024 supplementary, intensive and targeted culls to January 2025. How can a policy described by Labour as ineffective be implemented legally? There is no honour in retaining contracts that waste resources and distract from what really needs doing. 

Targeted culling

On 14th March 2024, under the previous Conservative administration, Defra launched a five-week consultation on the next steps to ‘evolve’ what they call ‘badger control policy’. If implemented, this would have involved ‘targeted’ culling of badgers, seemingly at the discretion of the Chief Veterinary Officer. A general election and subsequent Labour victory meant that it was lawyers acting for Defra’s Secretary of State Steve Reed (and not the Conservatives Steve Barclay) that responded to a Judicial Review Application [AC-2024-LON-002292] against the ‘future of badger culling’ Consultation, as reported here. The ‘targeted’ badger culling proposals based upon Low Risk Area ‘hotspot’ (or epidemiological culling) were scrapped, although the new Labour government was unclear about its reasons. Effectively this decision provided the legal relief that the legal case sought (i.e. no targeted culling was implemented) and so it did not proceed to a hearing. As previously mentioned, the Secretary of State Daniel Zeichner has now instigated a fresh review of future bovine TB policy. 

Low-Risk Area Culling

On the 22nd August 2024, a new consultation on licensing of a new badger cull  in the Low Risk Area appeared online. So Labour did not just re-authorise existing licences, they are started new licences in new areas, this one in Cumbria in the Eden valley north and east of Penrith. This had a 100% cull objective, repeating the failed epi-cull of the immediately  adjoining area, the subject of a report in 2023 (see here).  This cull that was demonstrably the most ineffective cull of all, because badger killing began when cattle testing had cleared all herds in the area, beyond those chronically infected. Labour have revised their public presentation to say that all culling will finish by the end of this Parliament – by 2029.

Test, Vaccinate, Remove (TVR)?

The direction of travel of a recent trickle of papers published by government scientists suggests that the new Godfray review will switch from recommending badger vaccination experiments to TVR experiments, possibly while cranking up ‘hotspot’ culling (which is targeted culling with a different name) to keep the ‘old science’ going. Will there be, as in 2013, a ghastly pilot of the new policy that would provide DEFRA with what they need to keep the NFU and others happy with continued culling?

How did we get here?

The intensive badger culls have been in progress since the policy began in 2013, bringing the official total killed to May 2025, to around 240,000.  Culled badgers have been predominantly healthy, killed on the premise of a hypothetical disease perturbation effect and supposed average 16% annual reduction in TB infections in cattle from culling, a concept designed by mostly Oxford academics that is now widely recognised as unsafe science, using unrealistic (and unexplained) extrapolation.

The February 2024 paper by Defra staff (Birch et al.) was being used to justify further culling in the March 2024 consultation, and falsely claimed that the culling programme thus far had been successful. With the Minister Steve Barclay stating “..bovine TB breakdowns in cattle are down by on average 56% after four years of culling..”. By sleight of presentation, he immediately muddles cause and effect. Authors of Birch twice acknowledge (on careful reading) that while they may speculate, the overall result cannot be attributed to badger culling: all disease measures implemented, including extensive testing, were analysed together with no control. There was no comparison of culled and unculled areas. It is far more likely to be cattle measures causing reduction in disease than badger culling, because decline began well before culling was rolled out. And in response to the introduction of annual SICCT testing in 2010 and short interval testing of infected herds. Birch et al also incorrectly under-reported the use of additional Gamma testing, which is a likely significant cause of disease decline. In truth, Birch cannot attribute benefit and provides no insight at all. Other cattle-based  measures were also introduced alongside culling. So it’s been more a case of  ‘Fake 56% News’ confirmation bias.

Writing in a preamble to Badger Trust’s report ‘Tackling Bovine TB Together’, key badger ecologist and original RBCT scientist Professor David MacDonald writes that the authors of Birch “… do not claim to have measured the consequences of badger culling, and indeed they have not”, and, “there is still no clearcut answer regarding the impact of this approach to badger culling on controlling bTB in cattle or, more broadly, whether it’s worth it.”

Badger culls have previously been justified using the guess-based ‘Risk Pathways’ approach of the Animal Plant and Health Agency (APHA) that purported to explain how disease arrives in a herd. Its ‘tick-based’ veterinary questionnaires implicated badgers as the default primary source of disease when adequate epidemiological information and investigation was lacking. Following publication of the report ‘A bovine TB policy conundrum in 2023‘ in April 2023, and with the speculative nature of their approach well exposed, APHA are now planning to use Whole Genome Sequencing (WGS) and a sample of dead badgers to try to justify culling on a local basis. These two methods of pinning blame on badgers fall desperately short however, as they do not prove an exact route or rate of transmission from badger to cow. Such a route may not even exist, or may be occasional or exceptional, occurring as a result of the constant infection of the countryside by infected cows. Badgers will just be getting bTB from cows, as with strain 17z in Cumbria, and rarely if ever giving it back. The proposed system for justifying badger-blame is still unscientific and unethical veterinary practice.

Why are APHA not checking back five or even ten years on moved stock to discover the improperly declared TB-Free source of new breakdowns?  It would show them the true source of infection.

Refuting peer-reviewed science showing industry-led culling has shown no disease benefit

In their March consultation, Defra are at pains to continue to refute a study in the journal Veterinary Record (18 March 2022) by Tom Langton and veterinarians Mark Jones and Iain McGill. They do this on the basis of an un-peer reviewed letter published at the same time, which used incorrect data and made incorrect assertions about the methodology used, that was later corrected with some confused and unsubstantiated remarks. So where, 2 years later, is their measured alternative? Nowhere, because they can’t produce anything, even holding all the extensive data on individual farms in secret, as they do and always have. There are many ways they could test the data, so why don’t they? Or have they tested it but don’t like the results? There was no peer-reviewed rebuttal to Langton et al. under the old Conservative leadership with Defra refusing to meet and discuss. We have blogged about this sorry tale here and here and here.

Langton et al. 2022, was done in the most logical and clear-cut way using all the data. It shows what happens as unculled areas become culled, from 2013 onwards. The paper has two main findings. The first is really good news for farmers, cows and badgers. Data suggests that the cattle-based measures implemented from 2010, and particularly the introduction of the annual tuberculin skin (SICCT) test are responsible for the slowing, levelling, peaking and decrease in bovine TB in cattle in the High Risk Area (HRA) of England during the study period, all well before badger culling was rolled out in 2016.

The second finding came from looking at the amount of cattle bTB in large areas in the High Risk Area that had undergone a badger cull, and comparing it with the amount of disease in large areas in the High Risk Areas that had not had culling. It included a six year period 2013-2019, so before and after culling was rolled out. Multiple statistical models checked the data on herd breakdowns over time and failed to find any association between badger culling and either the incidence or prevalence of bovine TB in cattle herds. The models that most accurately fitted the data were those that did not include badger culling as a parameter, suggesting that factors other than culling (cattle testing) were more likely to be the cause of the reduction in disease in cattle. Badger culling efforts appear to be to no effect. A summary of this research is available to read on our 18 March 2022 blog here. You can read an open access copy of the full paper here. A three minute video illustrating the work is available to view here.

Badger culling outcomes were always uncertain

With no analysis able to show a disease benefit from industry-led badger culling, the analysis from the original Randomised Badger Culling Trial (RBCT) remains pivotal to any decision to cull badgers. Published in Nature Scientific Reports in July 2024, Torgerson et al (2024) challenges the certainty of this original analysis. Read more about this here.

Commenting on this work, Professor David MacDonald writes “They found that the conclusions of the 2006 analysis are sensitive to the method of analysis used. Indeed, the analytical approach that Torgerson’s team judge to be the most obvious for the purpose, provides no statistical evidence for a culling effect, whereas a model comparison method aimed at selecting a model with the best out-of-sample predictive power indicates that the best model does not include the treatment effect of killing badgers. According to those statistics, killing badgers during the RBCT made no difference to the herd breakdowns, whether measured by either OFT-W or by OFT-W + OFTS.” In other words, badger culling in the RBCT showed no measurable disease benefit using the most appropriate analyses. On this basis, all badger culling must stop immediately.

New response from original RBCT authors

On 21st August  2024, and as a response to Torgerson et al 2024, two of the authors of the original analysis of the RBCT from 2006  (together with a third author) published two new papers in the Royal Society Open Science (here and here).

On 16th September 2024, a ‘Comment’ response to the new Mills et al. 2024 papers was submitted to the Royal Society Open Science: “Randomised Badger Culling Trial—no effects of widespread badger culling on tuberculosis in cattle: comment on Mills, Woodroffe and Donnelly (2024a, 2024b). This was accepted for publication on  April 23rd 2025 and published on 11 June. The new publication exposes the many flaws in the old RBCT analyses (Donnelly et al 2006 and Mills et al 2024a&b), and is endorsed by a senior biostatistician who describes work in Mills et al as “naive at best”. See more on this here.

The way forward

Rather than pushing for Test, Vaccinate & Remove (TVR)  as seems to be the DEFRA & APHA current direction of travel (together with continued intensive, supplementary and low-risk culling), it is time to stop and implement the cattle-based measures that would finally get the disease under control.

Dick Sibley has shown why cattle measures are failing (see here). A BBC documentary screened on BBC2 at 9.00pm 23rd August (and now available on BBC iplayer) does an excellent job of illustrating the problems of inaccurate cattle testing, and provides solutions – without culling badgers. Called  ‘Brian May – the Badgers, the Farmers and Me’, it is a must see, and make the realities of the problem and current negligent approaches more visible.

It is time to stop living in the past and putting faith in unsubstantiated beliefs that controlling badgers can play a significant role in the control of the bovine TB epidemic. 

 

Badger culls get go-ahead for 13th year

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Natural England have confirmed that the nine (9) supplementary badger cull licences issued in 2024 have been authorized for their second and final year 2025, with culling running from 01 June to 31 January 2026.

This is despite Director of Science Dr Peter Brotherton’s concluding advice, that “Based on the evidence, I can find no justification for authorising further supplementary badger culls in 2024 for the purpose of preventing the spread of disease and recommend against doing so.”

He has, as in 2024, been overruled for reasons that  will not be made clear for a few weeks, no doubt because if it is a re-run of 2024, the authorizations will also be added to the current legal challenge that our 2024 freedom of information response instigated.  DEFRA are making it quite clear to enquirers that they are not involved in the decision making, which is a stretch, and details should come out in the legal papers when the case finally comes to court. Unless expedited however, few badgers could be saved due to the lengthy judicial process.

A further 11 areas may be authorized for the final year of four-year culling and the low risk area cull in Cumbria may enter its second year. 

Infectiousness of cattle – how Bovine TB understanding went wrong in the 1980s

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Back in the day, and well before their ‘not-so-sensible after all’ 2001 merger  with the Department of Environment, Transport and the Regions (DETR),  the Ministry of Agriculture, Fisheries and Food, (MAFF), were influential in deciding what government should do about badgers.

Badgers  had being shown to be carriers of bTB, and capable of infecting cows, at least when locked in a small shed together with them for months. In their contribution to the 1980 Government review, (and tucked away in a long appendix), MAFF made significant claims that went wildly against the established veterinary thinking of previous decades. Previous established understandings had led to the effective elimination of the disease across most of Britain, no less. 

Despite this, in 1980 MAFF determined (on pure supposition) that badgers were heavily involved in disease transmission, via a (what now seem far-fetched) theory that ‘Cattle TB’ was in fact ‘Badger TB’, because infected cattle were rarely infectious. This was, they wrongly guessed, because  large lung lesions in cattle were mostly ‘closed’. Read our blog “How on earth did badgers get the TB blame?” and the more detailed report “Fifty years (1975-2025) of changing perspectives on bovine tuberculosis infection in cattle and badgers” for more information.

In the video linked below, ecological consultant Tom Langton shows how bad epidemiology altered the course of bTB control, sending scientists, civil servants, politicians, farmers and vets floundering  in the wrong scientific direction for over four decades.

Activism and the Scientist

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npj Climate Action is an open-access, online journal published by Nature Portfolio. It focuses on research and action related to mitigating the hazardous effects of global climate change. It aims to bridge the gap between scientific research and practical climate action, informing policies at both local and global levels.

A paper entitled “The activism responsibility of climate scientists and the value of science-based activism” (Anguelovski et al (2025)) has recently been published in npj Climate Action.  The arguments for the participation of scientists as so-called activists in the development and evolution of government policy are eloquently expressed and hard to disagree with. And these arguments transfer from climate science to many other areas of important environmental science, not least badger culling.

Quoting from this new paper, it is surely sensible that “scientists have the right and responsibility to engage in activism” because “their expertise and ethical responsibility position them well to change policy”. This has not been the case thus far with the science of badger culling, where independent peer-reviewed science has been dismissed by government scientists; the term ‘anti-cull activists’ has been used to try to slur individual scientists (and the peer-reviewers of their publications) and undermine the veracity of work that does not concur with the established Government policy view (see the un-peer reviewed letter in Vet Record,  DEFRA press release & CVO blog). No peer-reviewed science has been published since to justify the criticisms made in these pieces. Gideon Henderson has since left his post as Chief Scientific Advisor for DEFRA without commenting further on the matter or substantiating his intervention. Chief Veterinary Officer Christine Middlemiss remains in post.

How refreshing to read the recommendation the “..broader societal role scientists can play should be recognized and respected”. This has certainly not been the case with Government funded badger cull science, where there has been no inclusion of published scientists whose conclusions upset decades of Government funded work. Not only has there been inadequate dialogue, but the only route to release of critical data and policy rationale has been through Freedom of Information requests or grueling legal engagement. 

Badger Crowd is also happy to endorse the “call for the support of activists who engage with researchers in pursuit of evidence-based action.” As the paper’s abstract concludes, “Mutually supportive relations between science and civic groups will make science more horizontal, inclusive, and thus legitimate and impactful in the eyes of policymakers and society at large.”

Anguelovski et al (2025) includes a useful reminder of some important historical examples of scientific activists; “Think of Darwin’s debates with religious authorities, Snow’s work on cholera, or Rachel Carson’s Silent Spring. Entire branches of science (medicine, conservation biology) are defined by their activist agenda”.

Activism is one way the tribal behaviour of civil servants, can be opposed and overcome.

So, we will look forward to future involvement of all bovine TB activist scientists in the debate about the efficacy of badger culling and the direction of bovine TB policy. They have an important contribution to make. And it should have happened many years ago.

If you, as a member of the public, activist or scientist, support challenging the flawed science behind the badger cull and want to see a parliamentary debate on the issue, please sign the petition linked below calling to “End the Badger cull and adopt other approaches to bovine TB control”: