However, vaccination of cattle against TB is currently prohibited by EU legislation, mainly because BCG vaccination of cattle can interfere with the tuberculin skin test, the main diagnostic test for TB.

BBC: Q&A: The badger cull

He added that as well as looking whether vaccination programmes should be using the earlier strains, research to try and modify the BCG vaccine to make it more effective may be more successful with the older vaccines.

BBC: BCG is a vaccine which protects against TB