The Ministry of Defence defends sending army surgeons to train on live pigs, shot to replicate battlefield wounds, in a practice described as "impossible to justify" by animal rights groups.
British Army medical staff carry out the training at a Nato course in Jaegerspris, Denmark. Marksmen shoot the pigs so that drills can be carried out on them by military medical staff.
And MoD spokeswoman said the training saved lives. "This training provides invaluable experience, exposing our surgical teams to the specific challenges posed by the injuries of modern armed conflict," she said.
"This training has helped save lives on operations and by participating in the Danish exercises we minimise the overall number of animals used."
The government suspended British participation in the surgical training exercises, formerly known as "Operation Danish Bacon", in the summer of 1998 after they were brought to the attention of ministers.
The overwhelming majority of the UK's Nato allies do not shoot, stab and dismember animals for their military training exercises. - Mimi Bekhechi, Peta UK
But the courses were reinstated after it was determined there was "no equally effective alternative" and that it was "entirely appropriate and, indeed, necessary" for military surgeons to carry out training on animals.
Under the most recent exercise to have taken place, according to a report in the Daily Mail, 18 pigs were shot by sniper marksmen. The shot, targeting the underbellies of the animals, were designed to damage organs but not kill the pigs.
Surgeons then operated on the animals and kept them alive for two hours, before they were put down.
Claiming it would be illegal in the UK, Peta called for life-like dolls that "breathe" and "bleed" to replace the use of live animals.
Mimi Bekhechi, associate director for Peta UK, said: "The overwhelming majority of the UK's Nato allies do not shoot, stab and dismember animals for their military training exercises.
"The Ministry of Defence's decision to ship out members of the armed forces for deadly and cruel exercises in Denmark - which would be illegal if conducted in the UK - is impossible to justify medically, ethically and educationally."