His claim in today's Mail on Sunday that Lord Archer lied to his wife and seriously misled a High Court jury in order to save his political skin must surely be the coup de grace in the Archer saga.
Mr Stacpoole, 61, has been a hunted man since Ted Francis, revealed in the News of the World last week that Lord Archer had asked him to provide an false alibi for the former Mayoral candidate.
The picture that Mr Stacpoole paints of Lord Archer is far from that of the loving and loyal husband presented to the jury. Lord Archer carried on a passionate five-year affair with his personal assistant, Adrina Colquhoun.
Mr Stacpoole also reveals that he never told his story to the High Court because he was paid pounds 40,000 by Lord Archer to live in Paris for the duration of the trial - so that he could not be subpoenaed to give evidence - and for at least a year afterwards.
The Mail on Sunday, with the help of Michael Crick, Lord Archer's unofficial biographer, finally tracked Mr Stacpoole down to a hideaway in Thailand.
Mr Stacpoole has now said he will return from Thailand and tell his full story to Scotland Yard detectives who are building an ever growing dossier on Lord Archer's apparent attempts to pervert the course of justice.
Lord Archer and Mr Stacpoole grew close in the late 1980s when Lord Archer, according to Mr Stacpoole, was effectively separated from his wife Mary.
The two men used to drink together and once visited a strip club off Gower Street, near Tottenham Court Road, where Mr Stacpoole claims Lord Archer picked up a prostitute.
Three weeks after this incident he was called to a crisis meeting at the Conservative Party headquarters in Smith Square. He thought the Gower Street incident had been exposed but was told there was a problem with another women - Monica Coghlan.
Michael Stacpoole says that he cannot prove that Jeffrey Archer, forced to stand down as mayoral candidate last week, ever slept with Monica Coghlan but that he's certain the novelist lied in court.
"Whether he had sex with her or not, I don't know, because I was not in the room watching the performance and so I cannot say that he did bonk the girl. The odds were highly on it. Monica Coghlan's got no reason to lie. Archer we know to be a blatant liar," said Mr Stacpoole.Reuse content