Ingram, who outed Freddie Scappaticci as Stakeknife, says the document was given to him by a serving Special Branch officer. He claims it is a transcript of a meeting between the Provisional leader and his British intelligence handler about the human bomb tactic the IRA developed in 1990.

It is understood Ingram has shown the document to certain newspapers. He did not show it to the Sunday Tribune but gave this newspaper a transcript. The transcript carries no date and makes little sense out of context. Its veracity has not been proved and will leave many people sceptical. A Sinn Fein spokesman yesterday said: "We won't comment on something we haven't seen.

Who is Martin Ingram?"

Ingram says the document is one of a series and he is "hoping to produce further documents in coming months".

The alleged Provisional informer is not named but is code-named 'J118'. His handler is 'G'. Ingram named the alleged informer to the Sunday Tribune but this newspaper is not printing his name because of the lack of evidence provided.

The failure to prosecute this republican figure, despite what is said to be substantial police evidence relating to the murder of an informer, has previously led to speculation in security and republican circles that he is a spy.