Why was the use of Gamma interfreon testing, alongside use of the tuberculin test (SICCT), under-declared in APHA’s central bovine TB control evaluation paper (Birch et al 2024) last year, and also in the newly published ‘Godfray’ report?
Gamma reactors by cull year 2009 – 2023
A letter published today 19th September, in Veterinary Record, details the amount of supplementary Gamma testing that was introduced in the High Risk and Edge Areas before and during the post 2013 mass badger culls. It shows how Gamma testing was under-emphasised in the Birch et al. analysis on the effect of the poorly labelled ‘Badger Control Policy’, (see here). Considerable disease benefit is being claimed for badger cull in its first two years and beyond, but is far more likely to simply be linked to the increase in cattle testing with Gamma, as recorded publicly by number of gamma test reactors found.
What this shows is that Defra knew well that Gamma could find undisclosed infection, no surprise as it has been used in other countries for decades. They used it to help lower the spread of disease, then purposefully eased off, as badger culling was phasing down in more recent years. Who, you have to ask, was controlling this behaviour? And why?
As Badger Crowd has pointed out before (see here), all disease measures implemented, including extensive testing, were analysed together, with no control areas. There was no comparison of culled and unculled areas as the recent Godfray Review very strangely mis-reported.
Data presented with the Vet Record letter shows how easing off of the use of Gamma testing to supplement SICCT testing in 2022 is likely to have hindered disease control. This reduction in Gamma was said to be due to lack of EU funding, but this was surely predictable. So why were farmers and the public not told that the strategy was being derailed? A freedom of information disclosure in April 2025 concerning the likelihood of bTB freedom being achievable under present conditions of testing and cattle controls, produced the following response: ‘APHA has not yet produced models suitable for predicting whether TB eradication will be achieved in England by 2038, or when TB eradication will be achieved.’ The 25-year bTB eradication strategy published in 2014, with a 2038 projected target of bTB freedom (elimination or near elimination) now, on current trajectory, has an end point beyond 2060.
As has been pointed out many times before, there is an urgent need for the use of other immune-assay tests and phage testing to be authorised alongside SICCT and Gamma IFN-γ tests, and for farm vets to be provided with extensive new advice and guidance. With freedom to test bTB out from herds – this is mentioned in the Godfray report but it should have been front and centre.
The money raid on central government funds requested in the Godfray review would have been credible with a report triaging essential priorities. But instead, like the 2018 report, the 2025 report is muddled and incoherent. Progress, especially in England, Northern Ireland and the Republic of Ireland simply will not materialise if Defra continue along his line.
The long-awaited ‘Godfray’ report, a review of scientific evidence since 2018 concerning bovine TB in cattle, was published on 4th September. Commissioned by Defra, it is supposed to feed into a ‘comprehensive new bovine TB strategy’ that was announced in August 2024 by the incoming Labour government. It is the science that the new policy should be based on, so it is an important – and needs to be sound. More details will follow on the entirety of the report, but this is what was said about badgers and bovine TB
Panel epidemiologist: Professor James Wood
Chapter 6: The Disease in Wildlife focuses on badgers. The report does not deal head-on with the Royal Society Open Science pre-publication review by Prof Mark Brewer. This claimed that models suggesting ‘badger culling works’ were ‘naïve at best’. Instead, a newcomer to the issue, statistician Prof Bernard Silverman (a colleague of Christl Donnelly at Oxford University) has tried to rescue the situation & restore statistical validity to show some positive disease benefit.
Panel statistician: Professor Sir Bernard Silverman
Silverman presents a new set of models. He confirms (para. 65) in a massive ‘wake-up’ finding that a paper by Prof Torgerson’s study group in June of this year did show that the key 2006 RBCT paper by Donnelly and others, in short, got the modelling wrong. This has massive implications for a wide number of papers that have used that paper’s calculations to build further models. It must cause a tsunami of scientific correction, or the retraction of dozens of publications that have been used to promote badger culling over the last 20 years. This is potentially one of the biggest shake-up’s in biological science, for a generation. The ‘perturbation effect hypothesis’ evaporates, for example.
Panel member: Professor Glynn Hewinson
Instead of the huge significance claimed in 2006 for badger culling, Silverman has tried to produce a model that ‘just about’ finds an effect from badger culling, providing ‘weaker evidence for a positive effect’. But nevertheless, at first glance, it might save Oxford’s blushes. The problem is that he gets to this position in a manner that is both unconvincing, and incorrect.
Panel member: Professor Michael Winter
Firstly, there has been a major howler. Not just from Silverman but the two peer-reviewers asked to check his models, and Defra officials who supervised the process. Annex 4 of the Godfray report outlines the binomial model he has used, but gives the wrong information criteria (ic) outputs. These are standard applications that test how well the model fits the data. He claims to have used what is called Akaike, but instead presents Bayesian outputs. One assumes that this was not intentional, but rather a transcription error.
However, in addition to this, he has failed to address the fact that for binomial models with small sample sizes (the RBCT was an experiment with a small sample size – just ten paired comparisons), his binomal approach should have used a particular type of Akaike information criteria. When applied, results suggest that models showing a benefit from badger culling are those least supported. The best supported models are those that do not include badger culling, indicating badger culling had no effect. Even if he had decided that the Bayesian approach was the correct way to evaluate the models, the small sample size variant should have been used and this too makes badger culling the wrong model to favour from a statistical, hence scientific perspective. A pre-print outling the problems is available here.
So any ‘merit on both sides’ of the current modelling debate, the football equivalent of a score draw, does not apply as he had hoped. Torgerson’s analyses win handsomely on penalties and the RBCT is relegated.
For the benefit of stats geeks wanting to understand more, it is also fair to say that with Poisson regression, it is easy and quite natural (and now accepted by all), to include ‘time at risk’ in the model (as an offset), which is why Poisson regression would be the preferred method for the analysis. With binomial regression, to do this properly you need to have the complementary log-log function in the link. Again, when this is done, there is no effect of culling. Silverman has also not dealt with overfitting – there are too many parameters for the number of data points. He also fails to address the ‘all reactors’ argument that another chapter recommends needs ‘more research’. Could this be because finding in favour of using ‘all reactors’ would be yet another route to showing the data finds badger culling to have had no effect. Saving the RBCT is more important than admitting this essential pointer for cattle management?
The implications of a flawed report to the Minister are huge for Defra and Godfray, who chose Silverman to try to rescue the unsavable. It looks such a crude attempt that the new Minister (Zeichner has now gone) will have some difficult explaining to do. Do farmers get their money back for doing something pointless for the last 12 years, and do wildlife charities get compensation for rightly fighting, at huge cost, a scientifically botched policy? It’s going to be interesting. And if culling doesn’t work, neither will badger vaccination or TVR, which appears to be Defra’s new direction of choice. The second Godfray report could potentially be seen as a back-covering exercise to try to protect Oxford University, but it has not succeeded.
This is grounds for a major inquiry, with standards of scientific integrity and the impartiality of appointments under the spotlight. Badger culling would never have been sanctioned if the RBCT had got its statistics correct back in 2006.
On 19th August, Defra sent an email to ‘stakeholders’ announcing that as part of the work to refresh the bTB strategy, it will be “enhancing test sensitivity in cattle herds”. This is “to help identify infected cattle which may not have been detected by the skin test.” This news doesn’t seem to have been reported very widely, but has been covered by South West Farmer.
Defra say:
“At present, mandatory interferon-gamma (‘gamma’) blood testing applies to certain TB breakdown herds in the High Risk Area (HRA) and six-monthly surveillance testing parts of the Edge Area of England.We are working to extend gamma testing to all herds experiencing a new breakdown with Officially Tuberculosis Free Withdrawn (OTFW) status in the HRA and six-monthly parts of the Edge Area.”
“Therefore, farmers with eligible herds in these areas will be able to apply to APHA from 01 September 2025 for government-funded gamma testing as a voluntary option.All cattle with a positive gamma test result will be removed and usual valuation and compensation procedures will apply.”
“Using the skin and gamma tests together is proven to increase test sensitivity, particularly in herds where Bovine Tuberculosis has already been identified. This means infected animals can be detected and removed from the herd earlier, reducing the spread of the disease within the affected herd and the risk of future breakdowns after the herd has regained its Officially TB Free (OTF) status.”
This change is a voluntary one. If you don’t want to know whether your cattle have bTB using Gamma, you’re not obliged to find out. While the option for extra testing is welcome, it raises some interesting questions.
Strange Timing?
Government’s updated bTB control strategy is scheduled for spring 2026. It is to take its lead from a ‘Godfray Group’ review of new science published since the 2018 review, and this new review is expected shortly.
So why the urgency to push Gamma now? Could it be that APHA’s ‘Year End Descriptive Epidemiology Reports’ show that their long-term objective of reducing OTF-W (Officially TB Free Withdrawn) incidence to less than 1% has absolutely no hope of success & they really can’t afford to delay any longer?
Might Godfray have decided that OTF-S (Officially TB Free Suspended) is in reality a sufficiently accurate measure of new infection (see explainer), and the implication of this is that any fall in bTB has been modest and is levelling off to reflect the inadequate capacity of the flawed current approaches. Could the very high profile bTB breakdown at Clarkson’s Diddly Squat Farm have had some influence in this decision? (See Farmers Weekly take on this). Clarkson did say he would be speaking to officials at Defra…. It appears, incidentally, that he has bought from herds that have been in breakdown over the last five years or so.
It was use of Gamma that has reduced bTB since 2013
APHA’s scientific paper analysing the results of the Badger Culling Policy (BCP) (Birch et al 2024) claimed a 56% bTB reduction benefit over the period of badger culling. What it failed to articulate with clarity was that BCP was really a mixture of culling, increased frequency SICCT cattle testing and the introduction of Gamma testing in badger cull areas, and much earlier than indicated in that report.
Mis-describing the extent and timing of use of Gamma, that paper implied, with muddled wording, that badger culling was responsible for the disease benefit measured. The reality is that declines in bTB most closely mirror the introduction of enhanced cattle measures. Analysis of competing models in Langton et al 2022 suggested that the best random effects model was the one without badger culling as a co-variate; all the random effects models which included ‘cull’ failed to identify an effect of culling. Perhaps this is beginning to sink in at Defra.
What about the other cattle tests?
Anybody who has watched the BBC’s “Brian May: the Badgers, the farmers and me” will know that extensive efforts using a suite of cattle tests have been trialed for 10 years by vet Dick Sibley at Gatcome Farm in Devon. Working around Defra’s strict and problematic rules about the use of cattle testing, this groundbreaking work has shown not only how different tests can be used to identify the disease at different times in the life of cattle, but also how to use such a process to effectively manage infected animals to minimize spread. Where then, is the plan to utilize the full range of cattle tests that could be used to drive down disease?
So, is the new introduction of optional Gamma testing a token response to the clear failure of badger culling and recognition of a need for change? Alone, it will simply find more disease, delay OTF declaration and drive up OTF-S and OTF-W figures. An increase that misguided commentators will then no doubt claim is ‘due to badger culling being stopped’.
It’s too little too late; whether or not Defra attempt to cling to the flawed RBCT publications and badger blame game is about to be revealed. Their problem is that they surely won’t want to admit they wasted £100’s of millions and killed 250,000 badgers for nothing, so they may well be reluctant to accept what has become obvious to the world of science and statistics; badgers have not been shown to be a significant factor in the control of bovine TB in cattle herds.
The parliamentary summer recess has begun. There can be no more Parliamentary Questions until the recall in September. Which is more than a shame, because there are questions that still need to be answered about the badger cull and bovine TB policy, by a government that does not engage properly with many stakeholders and the public. Supplementary badger cull (SBC) and Low Risk Area licenses were issued in May, and badger shooting is underway, with more authorisations expected for intensive culling shortly. These last intensive cull licenses will almost certainly be issued later this month to allow even more culling in the autumn. But the science to support this policy has been successfully challenged in the literature, with independent verification and a call for proper investigation – yet we still have silence from a government that just wants to finish its ugly killing spree.
Zeichner visit to Gatcombe Farm
The Minister of State for Food Security and Rural Affairs Daniel Zeichner visited Gatcombe Farm in Devon a few weeks ago. This is the farm at the centre of the ground breaking Save Me TrustBBC documentary last year that was attacked by some of the nastier elements of the bTB world, including Defra-funded bodies. Gatcombe is where an innovative protocol for cattle testing has been investigated over the last ten years or so, using carefully managed, newer and more sensitive tests. Each test can be used to target bTB to better increase chance of detection. Used in combination, in a manner prohibited for general use by current rules, the new protocol has been successful in identifying infection that would previously be left hidden in the herd. Let’s hope Zeichner sees the potential to finally start on changes to policy that were needed many years ago, using the cattle measures that DEFRA staff have fought so hard to resist.
Godfray Review report postponed
The current review of bovine TB science, the first one published back in 2018, was commissioned by the new Labour government last year and was due to report by the end of June. But in June, this was officially changed to ‘from the end of June’. Badger Crowd understands that it will now appear towards the end of the year, but an exact time has not been announced. This could, perhaps, be partly due to the publication on June 11th of a paper in Royal Society Open Science that confirmed that previous core Government reference science, the RBCT, was in fact based on ‘a basic statistical oversight’, and that more plausible analyses of the results showed no effect of badger culling from the £50 Million experiment.
APHA produces a pre-print to oppose the 2022 appraisal finding no cull benefits
A pre-print has appeared on BioRxiv: ‘Evaluating the effect of badger culling on TB incidence in cattle: a critique of Langton et al. 2022’ authored by DEFRA’s Andy Robertson. Robertson has worked for TBHub, APHA, Natural England and is based at DEFRA. His publications have twice wrongly claimed badgers are a known maintenance host for cattle TB.
The new pre-print, three years in the preparation, claims that if badger culling had ‘worked’, (created disease decline benefit), the Langton et al analysismight not have detected it. As ever with DEFRA bTB publications, computer code for the model and simulations used is not provided, so it is impossible to check that what has been done is correct or plausible. Code was requested from DEFRA on July 21, but there has been no response at all.
Much of the text leans heavily on published studies that have now been shown to be uncertain at best. The Animal and Plant Health Agency (APHA) paper (Birch et al., published March 2024) in particular is misrepresented as evidence of a positive effect of badger culling. Accurate interpretation of that paper shows that there was no attempt in it to see if badger culling contributed to the general decline in bTB in herds under progressively tighter cattle testing methods. The critique glosses-over an important finding in Langton et al. 2022 (that Defra acknowledged at the time), that at the county level, bovine TB incidence stabilised, and started to decline, well before badger culling was rolled out.
Badger Vaccination
The governments new agreement to fund the NFU £1.4 Mn badger vaccination trials in Cornwall has been widely reported since January. It has been in the news again recently, yet there are still scant details available on the scientific and analytical protocol of the work. Aspects follows a similar project in Wales many years ago, that led to it being dropped as a strategic option.
Requests for further information from DEFRA have met the usual wall of silence. DEFRA’s Minister Sue Hayman half-answered a PQ on the project last week saying “Unlike previous badger culling studies, the Cornwall Badger Project is focused on testing different methods of delivering badger vaccination, rather than evaluating the impact on bovine TB in cattle.” So the use of badger vaccination as a tool in cattle TB control is not being measured? This despite NFU saying that is the essential question that needs answering. It all looks so half-baked and ‘un-joined up’ at DEFRA.
Jeremy Clarkson’s herd is OTF-S
As reported here, it was bad news for Jeremy Clarkson recently. Positive and inconclusive tuberculin tests on his cattle mean that Diddly Squat Farm now has the status Officially TB Free-Suspended. With viewing figures of 4-5 million, Clarkson is in a good position to put the disastrous government bovine TB policy into the public consciousness. Costing over £100Mn a year, the result of the policy has been an immense waste of time and resources. With a hidden epidemic that is still not being effectively detected, and 250,000 mostly healthy badgers culled, many cruelly, due to ‘statistical oversights’ and a government mired in its inability to get a proper grip. If Ministers want to do farming a huge favour, they will get the right experts to look at the evidence, and having procrastinated for over a year, instigate immediate radical change. Forget badgers, it is correct cattle testing and movement control procedures that will rapidly bring herds into manageable condition, as it did in the 1960’s.
Will anything new be offered before the intensive badger culling starts again in September? Probably not. The lack of urgency on this issue is incredibly disappointing. Whatever Labour’s manifesto intentions were, it seems that the civil servants have the whip hand here, holding on to their dogma and their wrong advice and roles, resisting rather than following the new science. It is the public purse, the farmers, cows and badgers who are paying the price of ineffective government.
The Diddly Squat Farm, owned by TV presenter Jeremy Clarkson and a part of the ‘Clarkson’s Farm TV show’, was the subject last week of multiple media reports on positive bovine TB tests in their small cattle herd. Perhaps the most dreaded event for any cattle owner and the prelude to an often long, expensive and heart-breaking series of events.
Reports suggest that a pregnant cow, with a calf that has been separated, is a positive reactor and to be slaughtered, while a bull and a few other cattle have produced tuberculin test results labelled ‘inconclusive’. Inconclusive results usually indicate an active infection, but not one where TB lung lesions are necessarily detectable.
England uses a SICCT test system that is failing and outdated; see the explainer here. In Wales, the SICCT test, with its extremely high specificity, is now read at ‘severe interpretation’, meaning that the ‘positive’ cut-off point (difference in bump size) is lowered so that some animals classified as ‘inconclusive reactors’ at the standard interpretation are now classified as full ‘reactors’ for management purposes. Wales has made similar progress to England without badger culling. Not finding TB on culture (in the lab) at post-mortem for some cows at slaughter, often happens simply because the infection is at too early a stage for the lesions to be visible to the eye, but that doesn’t mean they are not infectious.
The Daily Telegraph immediately, and relying on traditional anti-badger rhetoric, jumped to the conclusion that the infection was from badgers:
“Clarkson has spoken before about how badgers are rife on his farm and how he has tried to keep them away from his cows. But even with an Amazon budget and celebrity profile, the presenter was unable to stop transmission of the bacteria from badger to cow.”
But Clarkson confirmed that badgers have been heavily culled in his area in multiple yeas of culling ending last October. There are even reports that some of the badger setts in the area have been stopped up by others. So in an interview on Times Radio he is rightly uncertain as to how the disease arrived.
As with the majority of new bovine TB infections, the source is most likely to be undisclosed TB in purchased stock. Government’s external veterinarian of choice, Cambridge University’s James Wood claimed recently (on Farming Today) that:
“The challenge is with this [testing] system, the controls are imperfect, so that when we clear a farm with TB we know that a proportion that maybe as high as 25 or 50%, a proportion will have one or two animals that are still likely to be infected.“
Infection embedded in herds and traded onwards to new herds is the real problem. A simple check on the bTB status of herds that Clarkson has bought from in recent years will soon show if individuals are from herds that have had infection over the half dozen years or more. This is towards the upper bounds of the length of time that bTB is known to ‘hide’, due to some individual cows not responding to testing and the poor sensitivity (lots of false negatives) of tests used.
Clarkson recognises that the bTB system is a failure and questions why if TB meat can be eaten, the strict measures are absolutely needed. The fact that since pasteurisation was brought in bTB is not a significant human health risk is important, but Defra have rejected a rethink to relax massive public spending, and for it to be dealt with in a similar way to Johnes disease. Which is caused by a similar and widespread bacteria, spread by faecal contamination. Hence farmers face a draconian system imposed without access to alternative and better tests that Government have long-suppressed.
If Jeremy Clarkson can shine a light into the murky depths of bovine TB control policy and he does so with the appropriate seriousness, he will be doing farming a huge favour. But he will have to careful where he gets his advice and information from; that will dictate how successful he is. There are plenty of people giving bad advice, for all sorts of reasons.
“To ask His Majesty’s Government what assessment they have made of the paper by Torgerson and others published in the Royal Society Open Journal on 11 June claiming that other studies of badger culls contain methodological weaknesses; and what plans they have, if any, to ensure that the Cornwall Badger Vaccination Pilot has a peer-reviewed protocol before any work can continue.”
The reply from Sue Hayman was as follows:
“Work has started on a comprehensive new bovine TB strategy for England, to continue to drive down disease rates to save cattle and farmers’ livelihoods and end the badger cull by the end of this Parliament. The evidence surrounding bovine TB control, including recent studies such as the paper by Torgerson, is being independently reviewed by a panel of experts led by Professor Sir Charles Godfray, which the Government has reconvened. Unlike previous badger culling studies, the Cornwall Badger Project is focused on testing different methods of delivering badger vaccination, rather than evaluating the impact on bovine TB in cattle. The project is being delivered by the NFU in partnership with the Zoological Society of London, who have a track record of publishing peer-reviewed research on the subject of badger vaccination. The project will continue to be regularly reviewed by Defra as it progresses.”
“By working together to compare different approaches, we can develop a shared understanding of the evidence and use it to identify TB control solutions which are effective and sustainable.”
And it quotes a farmer as saying:
“What we hope to ultimately get out of [the project] is whether [badger vaccination] affects the cattle levels of TB – that remains to be seen, but I think it’s well worth doing.”
So Sue Hayman is telling us that “the Cornwall Badger Project is focused on testing different methods of delivering badger vaccination, rather than evaluating the impact on bovine TB in cattle”. Meanwhile, the researcher and farmer participant infer that the results will give an insight into the control of bovine TB in cattlebecause it seems they think or have been told that disease benefit in cattle is ‘likely’? This approach is highly questionable. The Government statement implies that three or four years down the road, we will still have no evidence of whether badger vaccination effects TB in cattle one jot.
Importantly, the PQ asked if any analytical protocol for the research and subsequent analysis would be published before the work starts to avoid a repeat of the problems of the Randomised Badger Culling Trial (RBCT) (see here). But this was not answered.
The Guardian article states:
“The project will assess three vaccination approaches to determine which works best: annual vaccination over four years, vaccination every other year or reactive vaccination based on TB infection on farms.”
But this is a three year project? Is ‘working best’ just a reference to a rough idea of TB prevalence change in badgers using a difficult test ?
The NFU said previously in their January project announcement and in defiance of Government policy:
“The NFU is clear that badger vaccination cannot be used as a direct alternative to culling and evidence is needed to give the NFU and wider farming industry the confidence that badger vaccination has any effect in reducing bTB in cattle, before proving its ability for delivery at the necessary scale, cost-effectively.”
So in summary, NFU are being given around £1.3 MN to see if farmers in some apparently badger-friendly areas of Cornwall can vaccinate badgers with a bit of training, and Sue Hayman says, quite rightly, that it will shed no light on whether vaccination is of any value in controlling bTB in cattle. In contradiction, the researcher quoted suggests the work will identify TB control solutions which are effective and sustainable. So why, in the midst of an expensive damaging disease crisis are the NFU being set up to spend public money on something that cannot deliver their stated needs? Do ordinary farmers in Cornwall know this? – apparently not according to what those involved are saying.
In any case the public, or at least independent specialists, should have access to the project design and the analytical protocol before work starts, whatever it is actually doing. For example if there are three treatment areas, will there be treatment ‘control’ areas and what proportion of badgers will be vaccinated, and what are the expected sample sizes?
Of course since the publication of Torgerson et al. papers (2024 & 2025), there is no sound scientific basis to continue with any badger culling or vaccination for bTB control. The RBCT did not show any benefit from badger culling, so any benefit from badger vaccination is unlikely. Cattle measures alone on the other hand, are proven to be effective. Are public funds being frittered again at a time when decisive action to protect badgers, cows and farmers remains long overdue and overlooked?
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?
A new article in Vet Times reports on the Torgerson et al (2025) paper published in Royal Society Open Science last month, that has prompted calls to stop all badger culling immediately. The badger culling policy has, it says, relied on a ‘basic statistical oversight’.
The article picks up on comments by the new paper’s reviewer, Biomathematics and Statistics Scotland director Mark Brewer, who argued that “in such a contentious area as this, it is naive to imagine that a single analysis by a particular group of scientists should be seen as sufficient”.
In a noticeable first and potential change of direction, the article quotes Chief Veterinary Officer Christine Middlemiss as saying that Defra is “really looking to protect our key species through vaccination and progress that with badgers, as a key wildlife species, but cattle as well.”
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.
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.
A prominent ecologist says an independent assessment of the latest study on badger culling is a “bombshell” takedown of the government’s evidence used to justify the policy. Tom Langton, a badger expert, said the conclusions by a top statistics professor should prompt the government to end the programme of shooting badgers to try to eradicate bovine tuberculosis (bTB).
Professor Mark Brewer, director of Biomathematics and Statistics Scotland, who reviewed the paper, praised the openness of earlier papers but wrote: “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.”
A study by Mr Langton and colleagues published by the Royal Society criticised scientists who believed badger culling was successful in reducing bTB, claiming they had made coding errors.
In the new study, Prof Paul Torgerson wrote: “The justification for lethal control of badgers to-date appears to have been based upon basic statistical oversight.”
Last week, The Independent revealed that government body Natural England had this year re-authorised supplementary licences to continue badger culls across England – against advice from their own scientific chief. The new culls will lead to an estimated 5,000 badgers being shot dead. The government has already begun establishing teams to increase badger vaccination and launched a badger population survey. It announced on Wednesday that badger TB vaccinations rose by 24 per cent across England last year, to what it said was a record high, with 4,110 badgers being vaccinated.
But controversially, ministers have also reconvened a panel of experts led by Prof Sir Charles Godfray, who has long backed culling and assessed the randomised badger culling trial (RBCT), concluding that culling reduced the spread in bovine TB.
Prof Torgerson wrote: “A very substantial number of publications that rest extensively or completely on RBCT statistical analyses may require major qualification or retraction.” And Mr Langton called for the earlier papers, on which successive governments have relied for evidence to continue culls, to be retracted.
He said: “The independent reviewer’s views should help take a wrecking ball to a large volume of accepted badger-culling science. “This shows how misjudgement can create bad government policy, if statistics are not checked properly and brings to life the many claims that the public have been cheated over badger culling for over a decade.”
Badger lobbyists argue that more scrupulous hygiene on farms reduces TB. The Wild Justice organisation, jointly led by naturalist Chris Packham, together with the Badger Trust, have won permission for a full judicial review of badger culling. The RBCT, which ran from 1998 to 2005, suggested a reduction in TB infections in cull zones, but its findings were disputed because of the “perturbation” effect, where badgers from targeted families moved further away from their natural areas, potentially carrying disease risk with them. It’s estimated 250 papers have been published using the results of the RBCT.
Epidemiologist Prof Christl Donnelly, professor of Applied Statistics at Oxford University, told The Independent that in the light of recent correspondence they would make some minor tweaks to some of their models.
“Crucially, the position does not change: repeated widespread badger culling can reduce risks of bovine TB to cattle inside culled areas, while increasing risks to cattle on nearby unculled land,” she said.
A spokesperson for the Department for Environment, Food and Rural Affairs said: “TB has devastated British farmers and wildlife for far too long.“We are rolling out a comprehensive TB eradication package that will allow us to end the badger cull and stop the spread of this horrific disease.
“This includes launching the first ever national wildlife surveillance programme to better understand the disease and work to increase badger vaccination at pace.”
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.
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.
In response to the new scientific paper published in Royal Society Open Science today, Natalie Bennett has re-iterated the Green Party’s call to bring an end to badger culling. She is quoted as saying:
“The Green Party has long said that the badger cull is cruel, ineffective in controlling TB in cattle, and unscientific, and here is a demonstration of particularly the last.”
“Policy should not be made, or continued, on the basis that ‘we must do something’, even if that something is known either to not work or be actively harmful. Yet that is the position the government is now in.”
“The science is clear that tackling biosecurity and testing in cattle is the only solution to this issue that is causing heartbreak and loss to so many farmers.”
“I repeat our calls for an immediate end to the killing of badgers in this terribly nature-depleted nation.”
On 19th August, Defra sent an email to ‘stakeholders’ announcing that as part of the work to refresh the bTB strategy, it will be “enhancing test sensitivity in cattle herds”. This is “to help identify infected cattle which may not have been detected by the skin test.” This news doesn’t seem to have been reported very widely, but has been covered by 
The parliamentary summer recess has begun. There can be no more Parliamentary Questions until the recall in September. Which is more than a shame, because there are questions that still need to be answered about the badger cull and bovine TB policy, by a government that does not engage properly with many stakeholders and the public. Supplementary badger cull (SBC) and Low Risk Area licenses were issued in May, and badger shooting is underway, with more authorisations expected for intensive culling shortly. These last intensive cull licenses will almost certainly be issued later this month to allow even more culling in the autumn. But the science to support this policy has been successfully challenged in the literature, with independent verification and a call for proper investigation – yet we still have silence from a government that just wants to finish its ugly killing spree.
The current review of bovine TB science, the first one published back in 2018, was commissioned by the new Labour government last year and was due to report by the end of June. But in June, this was officially changed to ‘from the end of June’. Badger Crowd understands that it will now appear towards the end of the year, but an exact time has not been announced. This could, perhaps, be partly due to the publication on June 11th of a 
As reported 
A prominent ecologist says an independent assessment of the latest study on badger culling is a “bombshell” takedown of the government’s evidence used to justify the policy. Tom Langton, a badger expert, said the conclusions by a top statistics professor should prompt the government to end the programme of shooting badgers to try to eradicate bovine tuberculosis (bTB). 