David Cameron has reaffirmed his commitment to badger cull pilots, which are set to resume this autumn.
The prime minister said he was "convinced" the controversial policy was the right way forward - despite the government's decision not to expand the extent of the cull in 2014.
Last year saw the beginning of two four-year pilot culls in Somerset and Gloucestershire, which have attracted huge criticism from animal welfare groups.
April saw environment secretary Owen Paterson confirm the government will not extend the cull to ten zones. The move was interpreted as a U-turn by the opposition but Cameron has now made clear he continues to back the cull.
“We are seeking to understand whether the controlled culling of badgers can play a part in reducing the incidents of TB in cattle. I believe that it can," Cameron told the Western Morning News newspaper.
"If you look around the world. The countries that have tackled TB in cattle have had to take action in terms of TB in wildlife. That was the case in Ireland. In Australia. So I'm convinced.
"But we need these pilots to go ahead to demonstrate that and then we can take the issue wider."
Question-marks over the effectiveness and humane nature of the pilot culls have only intensified the controversy, which will resurface later this year when the next culling season arrives.
Wildlife charities have written to the secretariat of the Bern Convention on conserving European wildlife and habitats, claiming the cull breaches its terms.
"The cull zones and surrounding areas are home to many protected endangered species of birds and mammals, and habitats such as heathlands, grasslands, meadows and forests," Mark Jones of the Humane Society International UK said last week.
"Removing or displacing large numbers of badgers from nature's delicate balance could be catastrophic for some of these species and habitats, so we're asking Bern to intervene and protect all of our wildlife from this disastrous cull."
Question-marks are also being raised about the necessity of the cull given new statistics showing the lowest rate of bovine tuberculosis - the disease which the cull is designed to combat - since 2004.
In March 2014 the proportion of new outbreaks discovered via testing was just 3.25%.
But Cameron added: "We've already spent £500 million on compensation payments to farmers in England and it could go up to £1 billion if we don't do something about this.
"I know some of the farming community want us to go even further but I think completing the two pilots, demonstrating that it is a system that works, will strengthen our hand in continuing to deal with the problem."
The animal welfare group Peta said the prime minister needed to stop "blindly supporting" the cull.
"While shooting more badgers will break up families and cause these much-loved, intelligent and curious animals to experience agonising and prolonged deaths – something Mr Cameron, as a deer stalker, may not care about – it would do nothing to solve the TB problem, which is predominantly caused by the intensive rearing and movement of cattle," a spokesperson said.
"Rather than championing the shooting of thousands of badgers in the hope that it will allow us to continue to use and abuse cows for their milk, the prime minster should be encouraging the public to curb its harmful eating habits. As health minister Anne Milton has pointed out, there is no evidence that milk improves the health of children."