A DOCUMENT purporting to show that Martin McGuinness, Sinn Fein’s chief negotiator, was an agent for MI6, Britain’s secret intelligence service, is a fake, according to senior security sources.

It was obtained by Martin Ingram, a former agent handler with the British Army’s force research unit, with the help of Kevin Fulton, a disgruntled former agent who is trying to pressurise his spymasters into paying him a pension.

The document was offered to the Sunday World and The Observer by a journalist who has worked extensively on stories with an intelligence angle. The Observer decided not to run it, neither did The Sunday Times, which obtained the document independently.

Ingram believes it is genuine, but last night Fulton said he knew nothing about it and had no idea whether it was authentic or not.

Ingram said the source of the document was a Special Branch officer who had worked with Fulton. Although Ingram had never met the officer, he had seen him leaving the document at a “dead letter box” or secret pick-up point.

“I am satisfied by the authenticity of this source, who has provided useful information in the past,” Ingram added. He gave the officer’s name to The Sunday Times for purposes of authentication. He had been told the officer could not be contacted because he was on holiday abroad.

Inquiries have confirmed that no detective using the name mentioned by Ingram is serving with Special Branch or CID. Neither is this person on the electoral register nor in the phone book. A uniformed constable with a similar name is serving in Northern Ireland but he said he knew nothing of Fulton, Ingram or MI6.

The name was not included on a list of RUC “handlers” that Fulton had previously given to The Sunday Times. This indicates the name, like the document, is a fabrication.

There were no security markings on the document, as would be usual with secret papers. Ingram said there had been MI6 classification on the original document, but this had been removed to protect the source. Ingram, who lives abroad, refused to make the originals available and turned down a Sunday Times offer to fly him to the UK to recover them.

The McGuinness affair may be linked to Fulton’s campaign to force the British Army to pay him a pension and a lump sum for the time he was an undercover agent in south Armagh.

In the past he has provided useful intelligence, even giving a possible warning on the Omagh bombing, but Sir Ronnie Flanagan, the former RUC chief constable, has said he is “an intelligence nuisance”.

This was a reference to an incident when Fulton burnt a vehicle kitted out with expensive bugging and tracking devices that he had been given for spying missions. In another incident he sent MI5 on a wild-goose chase looking for IRA arms across the UK. The cost of this exercise, motivated by a dispute with his handlers, was estimated at £2m (€2.9m).

The bogus document at the centre of the McGuinness affair purports to show McGuinness, code named J118, and an MI6 officer referred to as G, planning a series of proxy bomb attacks on British Army checkpoints across the province. The attacks, which took place at the end of 1990, claimed six lives.

The document is a transcript of a conversation but MI5, MI6, military intelligence and RUC Special Branch reports only ever contain summaries of what is said. “It is like no report I have ever seen,” said a senior intelligence officer. He added that, to his knowledge, McGuinness did not work for MI6.

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