IT is a death that has inspired speculation and rumour of dark involvement by the shadowy agents of the state for nearly three decades.

Now the controversy surrounding the "suicide" of SNP activist and lawyer Willie McRae, a prominent anti-nuclear campaigner, is to be turned into a play.

Some 29 years ago this month, on April 5, 1985, 61-year-old McRae left Glasgow to travel to his holiday home in Dornie, Wester Ross, for the weekend.

The next day he was found badly injured in his crashed car by two Australian tourists in a remote spot on the A87 near Kintail in Wester Ross.

Medical staff found a gunshot wound behind his right ear and police later recovered a weapon - which bore no fingerprints - some distance from where his car crashed.

He died the next day and while his death was ruled as a suicide, many believe he was murdered.

He was alleged to have been under Special Branch observation at the time of his death.

The play, Three Thousand Trees, written by poet and playwright George Gunn, will be performed at the Edinburgh Festival Fringe in August and is based around a fictional account of the last night of McRae's life.

Producer Mark MacNicol said he had been fascinated by the story of McRae while carrying out research for the play, and hoped it would bring the story to a new audience.

But he added the play would also raise a theme relevant to today's society of the idea of "Big Brother" surveillance and how far authorities will go to protect state secrets.

"We live in a culture at the moment where our civil liberties are being eroded," he said.

"Pretty much everybody now accepts that the state, your government, is watching you and your privacy has gone.

"But what is too scary for most people to accept is the possibility the state is capable of executing or eliminating or getting rid of a troublesome citizen.

"I believe the Willie McRae story, while obviously about one man, is very topical in 2014 as it represents that bigger picture in terms of the issue of government watching us and potentially being capable of getting rid of people."

At the time of his death, McRae had been campaigning against plans to dump waste from Dounreay in the sea.

He is said to have been in ­possession of highly sensitive papers on the case - which have never been located. As he left his office to travel to his holiday home, his last words to his office staff were "I've got them!", which some believe was a reference to the ­Dounreay case.

His house was also repeatedly burgled in the months running up to his death, adding to the mystery.

Gunn, who is based in Caithness, said he had been interested in the story of McRae's death since 1985.

"I was concerned about the case from the very beginning because of the sense of injustice," he said. "I wanted to present that case."

Actor Billy Riddoch, who appeared in Trainspotting, will take on the role of the fictional Willie MacKay in the play.

The cast also includes River City actor Adam Robertson, who plays an MI5 officer and is co-producer of the play. It will be directed by actress Libby McArthur.

It is not the first time the story of McRae's death has been used as a source of inspiration for fiction: Ian Rankin's 2011 novel The Impossible Dead has a character loosely based on him.