2038 Bovine TB targets on the scrap heap, with details of failed policy increasingly exposed

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.

References

Birch et al (2024)
Langton, Griffiths & Griffiths (2025)

 

Godfray ‘science’ report simply adds to the bovine TB chaos

Panel Chair: Professor Sir Charles Godfray

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.

 

Summer news roundup

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 Trust BBC 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 analysis might 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.

Why were you Wicked to Badgers?

Book Review:  A History of Uncertainty – Bovine Tuberculosis in Britain 1850 to the Present,  Peter J Atkins, 2016, Winchester University Press
(Link to the online chapters of this book (free subscription required) here.

By Tom Langton

 

Back in 2016, having just begun a detailed examination of the Randomised Badger Culling Trial (RBCT) (1), this book escaped my attention. Now with a tatty ex-library copy from ebay, its value and place is clearer. As with the 2019 review by Angela Cassidy (2), it is I believe a substantial contribution to the understanding of the English bovine TB (bTB) epidemic and control policy in the period since ‘badger blame’ emerged in the 1970s.

Peter Atkins, has been a prolific food and drink geographer and historian at Durham University, including inevitably, the disease-related issues. Much of the book is a detailed account of the technical and political context surrounding livestock management and milk production, including pasteurization since 1850, as a threat to human health. This is a compelling blend of what happened and why, regarding the once extremely debilitating and widely lethal bovine TB threat to human health in the UK.

Atkins book was published before the announcement of the 2016 badger cull roll out, which Atkins misjudged as unlikely to happen. Despite this, insight generally seems well evidenced and often convincing, and the book is especially worth reading in terms of what has unfolded since 2016.

Don’t be put off by the cover of the book, that shows nose to nose proximity between a tame badger and a cow, in an unlikely day-time event. This is, according to research done before and since publication, a rare event even at  night, which is when badgers are most active above ground. In fact, it is one of a group of photos that has unintentionally proliferated misunderstanding of the transmission of bovine TB from badger to cattle.

Although bovine TB and badgers occupies only the last quarter of the book (chapters 12-15), it manages to get through a good amount of epidemiological practicalities at pace, and provides bouts of eloquent summary. There is a useful collection of around 800 author-indexed references at the back of the book, several of them obscure, with handy library reference numbers too.

Spat between the ISG’s John Bourne and CSA David King

Chapter 12 on epidemiological understanding provides some useful detail on factors such as cattle herd density changes over time, government expenditure on disease control and potential infection pathways. Its thoroughness extends, at least to some extent, to referencing international examples and molecular consideration of spoligotype distribution. Chapter 13 is a rapid road trip from the period where bTB was found in badgers in 1971 in Gloucestershire, through the uncertainties of the badger-cattle disease relationship and infection of badgers by cattle. There is good descriptive summary, albeit with historical account of certain research findings as fact, rather than placed in any measured scientific context of the strength of findings. This is not a criticism as this was not a scientific appraisal.

There is a short history of badger culling from 1971, a rapid summary of the RBCT and the Independent Scientific Group 2007 report and of David King: the government chief scientific advisor’s critique of it. Plus, the spat between the Independent Scientific Groups’s John Bourne and King, that followed. Of some interest is the report that in 2007, it was the Labour government, under Gordon Brown and the MAFF-centric Lord Rooker, that laid the foundations for mass badger culling, even if there followed a delay by Hilary Benn until Labour lost the election to the coalition government in May 2010. There is some basic material on badger cull opposition and the period leading up to the culls starting, but nothing comprehensive. The threats from uncertainty and risk, the focus of the book, are well measured at appropriate points in the narrative. While several of the uncertainties are better understood due to research in recent years, the text for the most part stands the test of time well and is a good general foundation for the student.

Civil Service prone to massive policy mistakes and blundering?

Chapter 14 is likewise an admirable summary for the time of bTB testing protocols, and test accuracy. Examining what is termed the ‘recrudescence’ of the disease in England and Wales since its near eradication in the 1960s, it touches on important disease eradication cost-benefit issues and a more condensed history of disease administration, with even a brief sortie into cattle and badger vaccination.

But perhaps what is most interesting of all, is saved to the final chapter 15: ‘Is uncertainty the future?’. As the writer puts it, ‘what are the lessons the historical geography of bTB has for us?’ There then follows, as a warmup, a look at complexities of some of the spatial questions in bTB epidemiology, raised earlier in Atkins and Robinson (2013) (3) and more recently reinforced by findings from Whole Genome Sequencing. There is an amount of conjecture over ‘scenarios’ that to the historian may seem like useful wondering, but to the scientist perhaps are rather speculative.  Maybe a bit of original conjecture is okay, but it stands out a bit  in contrast to the bulk of careful documentary.

Then, for me the book turns even more compelling. It addresses the question of why the bTB response has been so sluggish and ineffective, and what is framed as the ‘grotesque cost’ of dealing with diseases of the intensive cattle industry: BSE, Foot and Mouth and bovine TB over the last decades. It looks at the punitive demise of MAFF after Foot and Mouth, and how the British Civil Service seems somehow prone to massive policy mistakes and blunders. Should, asks Atkins, bTB handling by Westminster be added to the ‘hall of infamy’ of policy disasters?  But then ‘no’ comes the answer, with a slightly unconvincing defence. His forgiveness is founded on his perception of complexity and uncertainty in the science.

Bang on cue, a sub-section is set up, that chimes with recent discussions over England’s covid-19 early response management entitled ‘A rule of experts?’. The building of policy-lead science (4) to address difficult questions is laid out, leading to the introduction of the concept of dealing with complex and politically tangled issues, framed as ‘wicked’. Based partly on the fact that the problem is dire, unforgiving, labelled as unsolvable and hence apparently justifying unconventional resolution. So ‘Yes Minster’ style consequentialism – where the ‘ends justify the means’: your often ‘tribal’ (5) bad behaviour is excused, and where whatever you decide, you become blameless.  Does this government approach sound familiar?

Wickedness unveiled

The last few pages of the book, ‘Bovine TB: a wicked problem?’ may both delight and annoy. They delve into the philosophy of addressing problems that are rated so unbalanced, complex, and frustrated, that the strategy is to manage them, based on continued uncertainty over long periods of time.  So bTB is allocated to ‘wicked’ philosophy (6), something that the very senior government officials and scientists may have latched on to at the start of culling as interest in its use began to grow (7). Meaning, that the uncertain outcome of badger culling wasn’t an important issue; it didn’t have to ‘work’ if it induced the livestock industry to accept tougher disease eradication measures that they were resisting. Such approaches are also nicely framed as a ‘clumsy solutions’. All government scientists and vets had to do, whether in the know or not, was roughly comply with a top-down ‘yes, it is the badgers’, undertake a bit of low inference analysis, then maintain ‘you will never actually know directly how much badger culling has contributed to disease control’ and ‘we are going to use every tool in the box’. This of course nullifies a range of professional and ethical pledges, and may be unlawful. But hey, this is a ‘wicked’ problem, these are different times and so anything goes? Those who have said badger culling is criminal may actually have a point?

One must ask who was ‘in’ on the badger cull wickedness, who fixed it, made it happen and who drove the car?  It is getting easier to see now. Anecdotally, government staff will apparently not deny it in private. This has been clear from multiple sources since Atkins book. But outwardly, in-post, their job comes first and they will follow the tribal line. This helps explain why Defra have reacted so ferociously (and clumsily) to the now emerging data on the badger culls (8) that shows them for what they are; ineffective. The problem must and needs long-term to remain ‘wicked’ for the emperor’s clothes to remain visible. But Environment Secretary Minister George Eustice has lost cull architects Ian Boyd and Nigel Gibbens, and those replacing them may not have been told and thus have greater exposure.

Atkins almost spoils it at the last, as Angela Cassidy did in her book in 2019. He had already come up with his own esoteric home-brew idea that badgers pose more of a risk at certain densities. He points at uncertainty in the epidemiology and the pathogenesis, but not to any deficit in ‘formal sector expertise’, which is a bit over-simplified. He denies ‘selfish individual motives or special interests’ which also looks a tad naïve, given the strength of influence of commerce in the mix. Atkins suggests no one is to blame, or that the blame is evenly spread, which is the diplomatic nice story, but  one cannot help feeling that in doing so, like Cassidy he drops into the ‘sticky trap’ of badgers and bTB (9).

Of course, scientific evaluation is not  Atkins forte,  and there is failure to balance scientific findings according to their limitations. BTB is a scientific problem and you can see as he cites and runs through much of the key relevant literature, that he is not pausing on the uncertainty and hindsight problems within them.

Despite this, Atkins logically foresees the time of effective use of cattle measures that were starting to bite in the High Risk Area as he finished this book, and that they need further tightening with better testing and/or cattle vaccination, to finish the job. Such disease control achievement however, is not the consequence of any ‘wicked’ approach. It is simply what would have happened with strong leadership and without badger culling. And, with all due credit, Atkins also rightly concludes that badgers are likely to be seen as a distraction to the bTB problem when all is said and done in years to come. Again, this book was published before the announcement of the 2016 badger cull roll-out and his last page makes salutary reading, as he was unaware of the mass butchering of largely completely healthy badgers that would immediately follow, and that should hopefully soon be abandoned.

This is a great ending if you are concerned by the repeating car wrecks of government veterinary epidemiology when addressing livestock disease control in England. And how the manipulation of logic and science for expedient high risk approaches, can be endorsed and nurtured in the tribal institutions in public service, given a few wicked people pulling the strings. 

A link to the online chapters of this book (free subscription required) is available here.

References

  1. Bourne J, Donnelly C, Cox D, Gettinby G, Mcinerney J, Morrisson I, et al. Bovine TB: the scientific evidence. A science base for a sustainable policy to control TB in cattle. Final report of the Independent Scientific Group on Cattle TB presented to the Secretary of State for Environment, Food and Rural Affairs the Rt Hon David Miliband MP; 2007.
  2. Vermin, Victims and Disease. Book review.
  3. Atkins, P.J. and Robinson, P.A. (2013) ‘Bovine tuberculosis and badgers in Britain : relevance of the past.’, Epidemiology and infection., 141 (Special issue 7). pp. 1437-1444.
  4. Kao, R. Simulating the impact of badger culling on bovine tuberculosis in cattle. Vet Record 176 February 18 2012. “An underlying problem in this debate is the contrast between the burdens of proof demanded by the scientific and policy constituencies. The burden of scientific proof requires near certainty in outcome; the classic limit for scientific confidence is that 19 times out of 20, a repeated experiment will produce a stated result (ie, the result is within the 95 per cent confidence interval).  Policy, however, must balance the efficacy of a potential measure with social, economic and political requirements, and in the event that a decision is to be made, it is made only when the balance of probabilities is in its favour. Thus, there is an inherent paradox in the need to take statistically rigorous, scientifically sophisticated recommendations and view them through the relatively fuzzy lens of sociopolitical realities.”
  5. Boyd, I. 2021. Scepticism, science and statistics. December 2021 Significance. The Royal Society of Statistics. P 42-45. 
  6. See Pellezzoni I. 2014 Technoscienza 5,2,73-91 and a raft of associated ideas discussed in the Atkins book and elsewhere. 
  7. Badger culling emerged from scientific endorsement but there was no real link between a large experiment with equivocal results and its real-time application. Culling badgers was simply ‘Bourne’s carrot’ using Kao’s (3) acceptance that an arguable balance of probability it might work (see (3) above) was sufficient. 
  8. Thomas E. S. Langton, Mark W. Jones, Iain McGill, 2022. Analysis of the impact of badger culling on bovine tuberculosis in cattle in the high-risk area of England, 2009–2020 Veterinary Record Vol 190 Issue 6. 18 March 2022 
  9. https://thebadgercrowd.org/vermin-victims-and-disease