A new report claims the “virtual extermination” of badgers in the Republic of Ireland has failed to stop the spread of bovine TB.

Although so many badgers have been killed that they are extinct in many areas, the level of TB in cattle is twice as high as in Britain, it says.

The study comes from Badgerwatch Ireland and the UK Badger Trust.

It has been released just before the British government receives an advisory report considering a similar cull.

“The grotesque extent of [the Irish] extermination proves that killing badgers does not control or eradicate bovine TB in cattle,” said Trevor Lawson from the Badger Trust.

“Badgers are a scapegoat for bad farming practices and an inadequate bovine TB testing regime. Our findings make a mockery of the demands for badger culling made in Britain by the National Farmers’ Union and other organisations.”

Badgerwatch Ireland and the UK Badger Trust have reviewed documents relating to the systematic destruction of badgers in the so-called Four Areas Project which operated in Cork, Monaghan, Donegal and Kilkenny from 1997 to 2002.

The project compared proactive and reactive culling of badgers in outbreak areas to try to determine which approach would have the greatest impact on the incidence of TB in cattle.

A review of the project for Defra found it to be the “best evidence yet of the fact of badgers contributing to bovine TB in cattle”; and the National Farmers’ Union highlights data in the project which it says shows effective badger control reduced cases of TB in cattle by up to 96%.

But the two conservation groups concentrate on what they regard as flaws in the project – and in the Irish Republic’s current control methods.

Their report says with 6,000 badger snares in operation every night in the Republic, the incidence of TB in cattle remains a major problem.

It claims the density of badgers in Ireland is now only 10% of that in equivalent habitats in South West England and yet, in 2006, Ireland slaughtered 9% more cattle with bovine TB than Great Britain – even though the Irish national herd is only 56% the size of Britain’s.

“If you’ve eradicated virtually all your badgers and you’ve still got twice the level of bovine TB in your national herd than you have in Britain, where we’re not slaughtering our badgers, then clearly Ireland has got it wrong,” Trevor Lawson told the BBC News website.

The groups believe their assessment supports the view that bovine TB in Ireland is largely spread by cattle. They say the disease rocketed in Ireland when pre-movement TB testing for cattle was abandoned in 1996.

It quickly reached the highest level ever recorded in 1999, with more than 45,000 positive tests. Badger culling continued throughout that period, their report states.

In Britain, the government-backed Randomised Badger Culling Trial (also known as the Krebs Trial), which ended in 2003, showed that culling could make the TB problem worse.