I want to make some progress or I will not get to the points raised by my hon. Friend the Member for Morecambe and Lunesdale.
Laboratory studies have demonstrated that vaccinating badgers with BCG can reduce the risk of infection and transmission of the disease. A four-year safety field study of wild badgers showed a statistically significant indirect protective effect in unvaccinated cubs born into vaccinated social groups, but vaccinating a large enough proportion of badgers to reduce transmission of disease and bring about a reduction of TB in cattle would take time to achieve and be costly to deliver, at between £2,000 and £4,000 per sq km per year.
In practice, it is inevitable that not all badgers in an area will be trapped and vaccinated. There is no evidence that vaccination protects already-infected badgers, and there is a risk that badgers from neighbouring unvaccinated areas may act as a constant source of infection. Nevertheless, computer modelling indicates that sustained badger vaccination campaigns could be beneficial in lowering TB incidence in cattle, but quantifying that contribution is likely to need a large-scale field trial, and it would take some years to collect the results.