Edinburgh Fringe Festival 2014: Mark Thomas's new show Cuckooed tells the story of the arms industry’s bid to infiltrate his campaign group

A member of Campaign Against Arms Trade allegedly passed information to BAE Systems over a period of seven years

Mark Thomas in ‘Cuckooed’, directed by Emma Callander at the Traverse Theatre in Edinburgh (Corbis)

Just weeks before Mark Thomas’s new one-man show about his experiences of corporate spying and betrayal was due to open in Edinburgh, he confronted a former friend at the centre of the story in a car park.

Seeking closure on a painful episode in his life and resolution for the show, the comedian and social activist asked Martin – whose surname he never reveals – to admit to the accusations that he had spied on their anti-arms industry group on behalf of Britain’s largest defence company.

It was the first time the pair had met in a decade. In Cuckooed, which opened at the weekend at the Traverse Theatre in the Edinburgh Festival Fringe, Thomas tells the story of his time with a group of campaigners and their betrayal by a member who allegedly passed information to BAE Systems over a period of seven years. Martin declined to talk, and Thomas now admits, on a personal level, that he will “never get the resolution”.

“Martin isn’t going to speak. That’s the resolution. On a political level, we have to begin to unpick this system of data theft and corporate spying.” He added: “It’s a very personal story but part of a bigger story that is important.”

The show was in development for two years, and uses testimony from other members of Campaign Against Arms Trade to tell the story, described as a “comedy of betrayal”. Thomas knew Martin for seven years, and said he had been “very active in the last four”. He added: “Ours was a friendship born in protest.”

Martin was CAAT’s campaign co-ordinator. Together, they protested at arms fairs, and he supported Thomas after he was arrested in 2003.

After a newspaper investigation revealed that the group had been targeted by corporate spying, senior members carried out an audit of the computers. It showed conclusively, according to several activists, that Martin was responsible. Thomas said he felt sick reading the files.

“The thing about betrayal like that is you feel foolish and ashamed. But afterwards, there is a questioning of your shared history.” In the build-up to the show, a decade on, Thomas said he “just wanted [Martin] to admit it”.

“There were a whole lot of conflicting emotions, because you get cross and angry, but I also felt, ‘You poor confused idiot, why did you do something that paid so badly?’”

As for being spied upon, “part of me thought: ‘Seriously, boys? There are bigger threats.’ Part of it is a badge of honour, part of you laughs at it, and part of you thinks it’s just f***ing insane.”