The tests, carried out at the MoD's secret biological and chemical research centre at Porton Down, Wiltshire, involve exposing pigs to high explosives to test their injuries. One such experiment was aimed at developing body armour.
Research reports obtained by the Independent on Sunday show how anaesthetised pigs with silver balls sewn onto the surface of their hearts have been suspended above guns fired to test injuries to their internal organs.
A report from 1991 describes how, in a test to help develop "protective clothing", anaesthetised pigs were strapped on to a wire mesh trolley and exposed to blasts "at either 600 or 750 mm from the mouth of the [explosively driven] shock tube".
At this distance the pigs suffered "a severe primary lung blast injury". Porton Down scientists measured the mortality rates of pigs injured in this way.
MoD animal experiments have increased by 51 per cent according to recent figures. This contrasts with a general fall of 10 per cent in animal experiments in Britain. Individual experiments have to be approved by the Home Secretary.
Vets, military experts and even Porton Down scientists have cast doubt on the necessity and effectiveness of using live pigs. "Problems arise when attempting to apply the present results in the pig directly to the situation in patients," concludes one experimental report. "The anatomical and biochemical dissimilarities between the pig and man must again be stressed in trying to extrapolate the current studies to human trauma."
Nigel Norris, a senior London vet, said: "I have a problem with the validity of these experiments. An unconscious animal is relaxed. A soldier is not relaxed. There is no merit in the pigs being anaesthetised - they might as well be dead."
Experts treating severe wounds in humans warn that animals under anaesthetic may still suffer pain from live tests. "We deal every day with victims of mines," said Rae McGrath, director of the Mines Advisory Group. "I assure you that with a major blast you'd need so much anaesthetic you'd be dead if you weren't going to feel it. As far as I know there is some limitation on the effect of anaesthetic."
Most animals are killed while still under anaesthetic, although some are kept alive to see how their wounds develop.
Matthew Taylor MP, Liberal Democrat environment spokesman, said: "People will be appalled that live animals can be used to test military equipment. Modern technology makes this unnecessary. We won a campaign to stop car manufacturers using animals. It's time the Government banned live animal tests for military purposes."
This week, Mr Taylor will ask Michael Howard, the Home Secretary, to provide details - previously kept secret- on live animal research at Porton Down.
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