Live pigs were blasted with explosives and forced to inhale mustard gas, and monkeys infected with anthrax during “disturbing and cruel” experiments at Porton Down, it was claimed today.

Scientists at the top secret military research establishment in Wiltshire were accused of causing "substantial" suffering to animals in the past two years.

The alleged evidence was collected by the British Union for the Abolition of Vivisection (BUAV) from papers published in scientific journals.

In one study, reported in the Annals of Surgery in 2010, explosives were said to have been detonated eight feet from pigs that had been anaesthetised, wrapped in blankets, and placed on trolleys.

The animals were said to have suffered blast injuries and blood loss, after which an attempt was made to resuscitate them. Eleven out of 28 died, it was claimed.

Other pigs suffered severe lung damage after inhaling phosgene and mustard gas, two lethal chemical weapons, according to the BUAV. They were eventually killed, it said.

In a further experiment, funded by the US Defence Advanced Research Projects Agency (Darpa), marmosets were infected with anthrax before being treated with an antibiotic, it was alleged. Four animals died and those still alive at the end of the study were killed and dissected, it was claimed.

This study was published in the International Journal of Antimicrobial Agents last year. There were no reports of pain relief or other supportive measures and the monkeys must have "suffered immensely" before experiencing a painful death, said the BUAV.

Two other experiments reportedly involved killing guinea pigs with a highly toxic nerve agent, and injecting mice with the bacteria that cause bubonic plague.

Michelle Thew, chief executive of the BUAV, said: "Although supporting the need to ensure the safety of soldiers and civilians in an increasingly dangerous world, the BUAV is opposed to deliberately causing suffering and death to animals in such disturbing and cruel experiments. We believe it is totally unacceptable to treat animals in this way."

A number of experiments were funded by US defence agencies, or conducted in collaboration with them, said the BUAV.

Porton Down is subject to the normal Home Office regulations intended to avoid unnecessary suffering by animals used in research.

But the Animal Welfare Advisory Committee, which previously advised the Ministry of Defence on the care of animals used in experiments, was dissolved in 2010.

Ms Thew added: "It is... unacceptable that at a time of growing public concern regarding the use of animals in research, there is no advisory body that could at least provide an element of independent overview on the care and welfare of animals used in warfare research."

The Defence Science and Technology Laboratory (DSTL) based at Porton Down said in a statement that it was "proud" of the research undertaken by its staff.

It added: "The remit to provide safe and effective protective measures for the UK and its Armed Forces could not, currently, be achieved without the use of animals.

"DSTL operates in strict accordance with the Animals (Scientific Procedures) Act. All the research projects that involve animals are licensed by the Home Office. As part of the licensing process, the researchers have to convince the Home Office that the work is required, that the results cannot be obtained without the use of animals and that every step has been taken to minimise pain and suffering to the animals involved.

"The Home Office, their inspectors and their independent Animal Procedures Committee (APC) make both announced and unannounced visits several times a year to ensure compliance with these guidelines. The MoD's Animal Welfare Advisory Council (AWAC) was dissolved as it duplicated this work."

International collaboration resulted in burden sharing and reduced the necessary use of animals in experiments, said the statement.

The BUAV said its science team obtained the reports from a search of the PubMed free access research database conducted between 2010 and 2012.