A new report claims the "virtual extermination" of badgers in the Republic of Ireland has failed to stop the spread of bovine TB.
The UK has been considering a large-scale cull of badgers
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.
Britain's National Farmers' Union accused the groups of being highly selective in their choice of figures.
It argued that controlled, selective culling of wildlife around infected farms in the Republic had brought considerable success in recent years in reducing the incidence of bovine tuberculosis.
The farming industry and many vets are adamant that badgers help spread the disease among cattle.
They would like to see a targeted cull aimed at infected populations of badgers in the UK, in "hotspot" areas including parts of South West England and in Wales.
The UK's Department for Environment, Food and Rural Affairs (Defra) says the government will assess the science, including data from the Irish experience, before deciding on the most appropriate solution to the problem in England.
It is due to receive recommendations from the Independent Science Group on Cattle TB this summer.
The devolved powers in Wales and Scotland are assessing the issues in tandem with England.
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".
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 the movement of 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.
The UK NFU accused the badger groups of twisting the available data to support their case.
The Union's Anthony Gibson argued that the Republic's policy of snaring badgers within a 2km radius of infected farms - where wildlife transmission was the suspected cause of the outbreak - had been an outstanding success.
He said it had resulted in a reduction in the number of cattle that needed to be slaughtered from 42,000 in 2002 to 24,000 now - a reduction of 46%.
THE KREBS TRIAL
30 areas of the country, each 100 square km
10 culled proactively, 10 reactively, 10 not culled
Badgers culled through being caught in cage and then shot
Incidence of bovine TB measured on farms inside and outside study areas
Reactive culling suspended in 2003 after significant rise in infection
Trial cost £7m per year
"That's an impressive result," he told BBC News.
"Ireland has always had a much worse problem with TB than we have; the fact is that they're managing to reduce their incidence of TB quite significantly, whereas over here, in the first two months of this year, the number of cases went up by 10%."
He said government advisors could learn valuable lessons from the Irish experience.
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.
Reactive culling raised TB incidence by 25%. A proactive regime lowered incidence inside the target zone, but resulted in an increase in surrounding areas.
When contacted by the BBC, Ireland's agriculture ministry said it was considering its response to the conservationists' report.