It is something that could have come straight out of the pages of a John le Carr spy novel or a scene from a James Bond film, writes PAUL WARNER.

It involved a subversive plot to develop a chemical warfare programme that reached the heart of the South African government during the dark days of the apartheid era and has links with a man buried in Lower Heyford.

And the main players were not just South African intelligence agents but also secret servicemen from this country, notably, MI5.

The aim of the chemical warfare programme was not based on national security, but was more sinister. It aimed to silence black activities during the last throes of the apartheid regime.

Details of the chemical programme emerged during the Truth and Reconciliation hearings which linked British intelligence with the covert South African operation.

And one charity worker believes her fiance became embroiled in the dark world of counter-intelligence, which led to his death.

Peter Martin, from Kirtlington, a former director of a counter-terrorism London advice firm, Special Training Services, died of a stroke in 1992, aged 62. He is buried in St Mary's Church, Lower Heyford. But his former fiancee Rosemary Durrant, 69, who used to live in Lower Heyford, but has since moved to London, believes there was a sinister plot to murder him.

Mr Martin was an apparently healthy man who suddenly died of a stroke. Rosemary does not believe his death was due to natural causes and believes he was killed because of his knowledge of the South African programme.

Rosemary said: "He was very terrified that he would be assassinated.

"I'm looking for justice and the truth. There are still a lot of unanswered questions which need to be brought out in the open. I'm hoping that the truth about this great injustice will be uncovered."

Even today, fearful for her own safety, Rosemary screens all her phone calls and refuses to pose for photographs.

The deaths of Mr Martin and of five other people were the subject of a Panorama investigation called Plague Wars, televised last Monday, in which Rosemary appeared.

In the programme, it was revealed that Mr Martin was approached by the South African apartheid regime in the 1980s about biological and chemical warfare programmes. Mr Martin became suspicious and reported his meetings with South African intelligence to MI6. MI6 told Mr Martin to keep them informed and even arranged for him to visit the Government's nuclear, biological and chemical training establishment in Wiltshire.

But Mr Martin, Panorama suggests, may have been murdered because of the potentially damaging information he possessed.

Panorama revealed that five other people who knew of the programme had also mysteriously died of strokes.

The programme featured the case of a South African soldier, Garth Bailey, who learned about the germ warfare programme.

He died suddenly of a stroke in 1983, aged 29, but his death may have been caused by snake venom, Panorama suggests.

Lt Gen Niels Knobel, former surgeon-general of the South African Defence Force, told the programme that the country received secret manuals 'either stolen or given to us' from defence establishments in this country.

Rosemary raised her suspicions about her fiance's sudden death to doctors at the John Radcliffe Hospital, in Oxford, although a post-mortem failed to show anything.

She added: "The suggestion is they could have used untraceable poisons. I just want to find out the truth behind how he died. He was a wonderful man." The Truth and Reconciliation hearings heard how scientists were investigating new ways of developing chemical and biological weapons, including tests on ways of spreading cancers and poisoned t-shirts.

The commission also heard how the Rev Frank Chikane, an adviser to President Nelson Mandela, survived attempts to poison him, including dusting his underpants with chemicals that seeped into his skin.

When he collapsed in America in 1989, the FBI concluded his clothes had been dusted with phosphates supposed to trigger a heart attack.

Project Coast, the commission found, was being led by Wouter Basson, a former special forces officer and heart specialist to the former South African president PW Botha.

Before his death, Basson had approached Mr Martin for information about biological and chemical warfare, claiming it was for defensive purposes for troops fighting in Mozambique and Angola.

A Panorama spokesman said: "It was a very thorough investigation which was put together over many, many months. Plague Wars revealed some very worrying aspects about chemical biological warfare programmes around the world."

Converted for the new archive on 30 June 2000. Some images and formatting may have been lost in the conversion.