The Government must not initiate a blanket cull of badgers as a way of tackling the surge in TB, scientists at a Midland university have warned.

Biologists at the University of Warwick said they had come up with a tool which could help target infected badger setts in a bid to help control the dis-ease in cattle.

Farmers are convinced there is a link between a rise in bovine TB in cattle and the presence of the disease in wildlife although wildlife groups dispute the claim.

The Government is currently considering a consultation on how to deal with the disease, which could include a badger cull.

The Warwick researchers said they used molecular methods to examine the prevalence of Mycobacterium bovis, which causes TB, in soil collected from badger setts and in badger faeces on cattle farms in six endemic regions of the UK.

The research, published in the Royal Society's scientific journal Biology Letters, found M.bovis was prevalent in the soil of badger setts on 78 per cent of farms sampled and in 56 per cent of badger faeces on farms sampled.

On contaminated farms, an average 43 per cent of the setts and 29 per cent of faeces were positive.

In related research, they have also shown the organism to persist in the environment for months.

Dr Orin Courtenay, one of the leading researchers on the project, said: "We do not advocate culling badgers to control bovine TB, particularly in light of the scientific results emerging from the randomised badger culling trial.

"However, if the Government takes the decision to continue to cull badgers we would prefer that culling is targeted at diseased and infectious animals - cattle, badgers or other wildlife hosts - rather than see a policy of untargeted culling which by nature includes removal of healthy and uninfected animals. With some further scientific evaluation, a "sett test" based on molecular technology could provide a tool towards achieving this aim."

The results suggested that once the organism was excreted into the environment by cattle, badgers, or other wildlife, it could act as a source for further transmission.

Therefore, an eradication of badgers would not mean the area would be then free of the disease.

The researchers also carried out a more detailed study of high-density badger populations in Oxfordshire, which is currently free of TB, and Gloucestershire, which is known to have problems with the disease.

In the Gloucestershire population, they found all the examined badger setts to be contaminated with M.bovis, whereas none of the samples in the Oxford-shire population were positive.

In the past, a lack of precise knowledge of the infectious status of badger populations has led many to advocate blanket culling of badger populations.

This action was taken in a badger culling trial, which led to the social disturbance among surviving badgers with consequential increases, rather than decreases, in TB infection rates in cattle.