Bovine tuberculosis (TB) is expected to cost British taxpayers nearly £100m in 2014. Scientific evidence is a vital weapon in the fight to protect cattle from TB. Why, then, has the government just fought and won a legal battle to avoid consulting independent scientists on its most high-profile TB control effort?

Wild badgers play a role in transmitting TB to cattle, and culling badgers seems an obvious solution. A new round of badger culls is about to start, but it is risky . A complex interaction between badger behaviour and TB transmission means that the results of culling could, depending on various factors, increase TB levels, instead of reducing them. To add to that, badger culling is expensive.

This is why, in 2013, the government started a pilot that it hoped would be give them a cheap and effective way to control cattle TB. Farmers, rather than government, would pay for the culling. And, rather than being cage-trapped, badgers would be shot in the wild.

This pilot was started in just two areas – and for good reason: the whole approach was untested, and the stakes were high. Marksmen shooting at night might endanger public safety. Shooting free-ranging badgers might cause suffering. And, worst of all for the aims of the approach, failing to kill enough badgers, fast enough, would worsen the cattle TB situation that the culls were intended to control.

In the face of such uncertainty, the government adopted a commonly used approach. It appointed an Independent Expert Panel to assess the safety, humaneness and effectiveness of the pilot project. The expectation was that this panel’s conclusions would reflect scientific evidence, whether or not they supported government policy.

Bring in the experts

The Independent Expert Panel found that farmer-led culling was far from effective. Tasked with killing at least 70% of the local badgers within a six-week period, cull teams only managed to kill between 28% and 48%. Culling periods were extended, but still the total kill rose to only something between 31% and 56%, according to government figures. Unless more badgers could be killed, and faster, farmer-led culling risked worsening the problem it was intended to solve.

The 2013 culls also failed to meet their targets for animal welfare. Between 7.4% and 22.8% of badgers were still alive five minutes after being shot and were assumed to have experienced “marked pain”.

Despite facing these failures, the government decided to repeat culls in the same areas in 2014. If effectiveness and humaneness could be improved sufficiently, culling might be extended to more areas in 2015. If not, the government might need to reconsider their policy. One would think, then, that measuring effectiveness and humaneness would be a central goal of 2014’s culls.

Then ignore their advice

The Independent Expert Panel, together with government scientists, selected the most accurate and precise ways to estimate the effectiveness and humaneness of the 2013 culls. Measuring effectiveness is challenging because – being nocturnal and shy – badgers are hard to count. The panel overcame this problem by using genetic “fingerprints” to identify badgers from hair snagged on barbed wire. They measured humaneness primarily through independent observers recording the time that shot badgers took to die.

The panel recommended that the same approaches be used for subsequent culls. But the government rejected this recommendation. This year there will be no attempt to count badgers in the cull areas, either before or after the culls. The time badgers take to die will not be recorded. There will be no oversight by independent scientists.

Instead, the effectiveness of the culls which start tonight will be judged using a method so utterly inadequate it was barely considered in 2013. Key data will be collected by marksmen themselves: people with a vested interest in the cull being designated “effective” and “humane”, who in 2013 collected data so unreliable it was considered unusable by the panel. Available information suggests that any future claim that the 2014 culls have reduced badger numbers sufficiently to control TB will be completely baseless.

Why the change in approach? Government cites cost, and hired some expensive lawyers to defend its position when the Badger Trust sought, and eventually lost, a judicial review of the decision to scrap independent scientific oversight of this year’s culls. Yet the cost of pushing forward with an ineffective culling policy would far outweigh the cost of properly assessing effectiveness and humaneness.

Government has repeatedly referred to its programme of badger culling as “science-led”. One would expect a science-led policy to entail gathering reliable information on management outcomes, and using this and other evidence to inform future decisions. Choosing – against formal expert advice – to collect inconsistent, inadequate and potentially biased data is an insult to evidence-based policymaking. When ineffective culling can make a bad situation worse, failing to collect the evidence needed to evaluate future policy fails farmers, taxpayers and wildlife.

Next, read this: Cattle herd model reveals best ways to halt spread of TB – and a badger cull isn’t one of them