About one in seven badgers killed on the roads was suffering from TB, according to a new survey.

The findings come from the Department of Environment, Food and Rural Affairs' Badger Road Traffic Accident Survey covering the years 2002 to 2004 and are based on TB tests carried out on roadkill badgers collected from seven counties, including Worcestershire, Herefordshire and Shropshire.

It was carried out on the advice of and supervised by the Independent Scientific Group on Cattle TB and was designed to establish whether the level of bovine TB infection in dead badgers, collected from road accidents, reflected disease prevalence in the badger population in the area.

This was done by comparing data with findings from the Randomised Badger Culling Trial.

The survey was carried out in the RBCT counties of Cornwall, Devon, Gloucestershire, Herefordshire and Worcestershire. Shropshire and Dorset were also targeted as comparison counties.

The data collected can be used to estimate prevalence at county level. In general, the prevalence of infection in badgers was higher in the northern group of counties involved (Gloucestershire, Herefordshire, Shropshire and Worcestershire) than those in the southern group (Cornwall, Devon and Dorset).

However, Defra said insufficient badgers were collected through the RTA survey to allow parish level prevalence estimates to be made.

Animal Health Minister Ben Bradshaw welcomed the publication of the data.

He said: "These findings show that, even in those parts of the country worst affected by bovine TB, most badgers test negative for the disease.

"They also show no clear correlation between the levels of TB in cattle and badgers.

"These latest findings will be used alongside other research and advice from the UK and abroad to develop policy on tackling bovine TB."

Shadow agriculture minister Owen Paterson said: "Conservatives will continue to campaign for healthy cattle and healthy wildlife." Ben Bradshaw