Scientists blasted pigs with explosives, infected monkeys with biological weapons and poisoned guinea pigs with nerve gas.
The tests were carried out at the Defence Science and Technology Laboratory at Porton Down in Wiltshire.
The base is where scientists confirmed that the nerve agent Novichok was used to poison Sergei and Yulia Skripal and kill Dawn Sturgess in Salisbury.
Figures seen by the Daily Star Sunday show that between 2010 and 2017, 48,400 animals were killed.
Last year, in a variety of tests, scientists shot, blew up, gassed and poisoned animals with chemical and biological agents as part of the Ministry of Defence’s secret weapons research programme.
In one experiment, guinea pigs had the nerve agent VX applied to their backs in order to see how the chemical – known as a bioscavenger – would affect them.
The animals were observed after being poisoned and given a score for their symptoms – the higher the score, the worse the animal’s condition.
Symptoms included “gasping” and “writhing”. Animals still alive at the end of the tests were killed and dissected. The Government maintains the tests are vital to protect troops from a wide variety of weapons which could be used against them.
But animal rights’ campaigners claim the experiments are unnecessary and the numbers being killed are “alarming”. Most of the pigs were killed during explosives tests as part of a research programme to develop more effective body armour.
It follows the deaths of hundreds of soldiers killed by improvised explosive devices in Iraq and Afghanistan.
Pigs were wrapped in body armour material before being seriously injured or killed by explosives. After the tests were finished, scientists studied the animals to assess which body parts had been protected.
In other tests monkeys were injected with biological weapons such as anthrax, while scientists recorded the level of pain they experienced and how long they took to die.
Other animals were forced to breathe chemical weapons such as mustard gas, which burns the lungs and causes huge blisters on the skin.
Jessamy Korotoga, from campaign group Animal Aid, said: “Animals suffer and die in so many different types of animal experiments, but there is something especially dark and troubling about warfare experiments.
“To deliberately expose live animals to compounds, simulated blasts and biological pathogens which are known, and indeed developed, to cause extreme suffering and death, is morally unconscionable.
“A civilised society, in the 21st century, should not be involved in such macabre practices.”
A Ministry of Defence spokesman said: “The Defence Science and Technology Laboratory is responsible for developing and creating indispensable technology and equipment to protect the UK and its armed forces.
“This could not, currently, be achieved without the use of animals in research.”