Martin McGartland, who survived an assassination attempt and suffered severe injuries after jumping from a building to escape the IRA, said he is angry about the way his story has been treated in the film Fifty Dead Men Walking.

The Canadian-British production, starring Oscar-winning actor Sir Ben Kingsley and actor Rose McGowan, will receive its worldwide premiere at the Toronto International Film Festival in Canada on September 10.

Mr McGartland, who is threatening the film makers with legal action, has said he hopes to fly to Canada to mount a protest to coincide with the premiere.

He has claimed the film, inspired by his 1997 book about his dramatic life story, Fifty Dead Men Walking, fails to make it clear that he was never a true member of the IRA and only joined the organisation as an agent for the Special Branch.

He added that he objected to a number of scenes in the film, including one in which he is depicted as witnessing the IRA torture and murder of a suspected informer.

"I should not have been placed in that position, I was never in such a position, never, ever," he said.

He added: "I have said right from the beginning that had someone come along to make a film of my book I would have been ecstatic because to me the book is a story that has everything that would make a really good film.

"I cannot understand why they had to change things to that extent," he said.

In his best selling book Mr McGartland tells of how he was starting working for the Special Branch as an informer two years before infiltrating the IRA in 1989. His cover was blown in 1991 after he tipped off the police about a planned attack on a pub in Bangor, Co Down. He was kidnapped by the IRA but escaped execution by jumping from a third floor window.