Animal welfare campaigners have vowed to fight badger culling in England after trials were given the go-ahead by Environment Secretary Caroline Spelman.
Six-week trials will take place in two areas next year and could lead to a wider cull across the country as part of efforts to tackle TB in cattle.
Mrs Spelman told the Commons a vaccine for the disease would take too long to develop and it was difficult to administer to wild badgers, which needed to be trapped first. Culling could reduce the incidence of bovine TB by 10%, she suggested.
Vets' leaders welcomed the move, saying it was "undisputed science" that killing badgers was effective but that controlled shooting had to be tested as a method.
British Veterinary Association president Carl Padgett hailed the trial as "a major step on the long road to tackling this devastating disease".
However, the Humane Society International (HSI) said it would submit a formal complaint to the 1979 Bern Convention on the Conservation of European Wildlife and Natural Habitats. It said the cull lacked "legitimate purpose", posed a significant threat to badger populations and that ministers had failed to examine alternatives.
HSI executive director Mark Jones, himself a vet, said Mrs Spelman's decision appeared to be in "clear breach" of the Bern Convention and amounted to "institutionalised cruelty".
The RSPCA accused the Government of being "more interested in killing badgers than vaccinating them" while the Badger Trust said it was "clearly very disappointed" and would consult lawyers to decide what action could be taken.
NFU president Peter Kendall said: "This is another massive step forward in achieving our end goal of a healthy countryside - both for badgers and for cattle.
"I commend Defra for introducing these two pilot areas to confirm the effectiveness, humaneness and safety of controlled shooting."