The Badger Trust is mounting a legal challenge to halt an extension of the controversial badger cull pilot, it has emerged.
The opponents to the cull in Gloucestershire have formally warned the authorities to abandon the shooting or face a High Court challenge.
The challenge would be on the grounds that a plan to more than double the killing period is illegal, the Trust said.
Around 30% of an estimated 2,350 badgers were killed during the six-week pilot, rather than the planned 70%.
And in west Somerset 850 badgers had been culled during the pilot - 60% of the local population.