Badgers (Meles meles) were first identified as carriers of M. bovis in 1971, but the report of an independent review committee in 1997 (the Krebs Report) concluded: "strong circumstantial evidence [exists] to suggest that badgers represent a significant source of M. bovis infection in cattle... [h]owever, the causal link... has not been proven". In essence, the contribution of badgers 'to the TB problem in British cattle' was at this point a hypothesis that needed to be tested, according to the report. The subsequent Randomised Badger Culling Trial (designed, overseen and analysed by the Independent Scientific Group on Cattle TB, or ISG ) examined this hypothesis by conducting a large field trial of widescale (proactive) culling and localised reactive culling (in comparison with areas which received no badger culling). In their final report, the ISG concluded: "First, while badgers are clearly a source of cattle TB, careful evaluation of our own and others’ data indicates that badger culling can make no meaningful contribution to cattle TB control in Britain. Indeed, some policies under consideration are likely to make matters worse rather than better. Second, weaknesses in cattle-testing regimens mean that cattle themselves contribute significantly to the persistence and spread of disease in all areas where TB occurs, and in some parts of Britain are likely to be the main source of infection. Scientific findings indicate that the rising incidence of disease can be reversed, and geographical spread contained, by the rigid application of cattle-based control measures alone." On 26 July 2007, the Minister of State, Department for Environment, Food and Rural Affairs (Lord Rooker) said, "My Lords, we welcome the Independent Scientific Group’s final report, which further improves the evidence base. We are carefully considering the issues that the report raises, and will continue to work with industry, government advisers, and scientific experts in reaching policy decisions on these issues."
