Newly released police files have revealed details of a failed attempt to blackmail a London pornography baron and property magnate in the 1970s.
The late Paul Raymond - once dubbed the "King of Soho" - led the men to police by arranging to hand over £15,000 in a series of recorded phonecalls.
The men, Eden Reid and Douglas White, were jailed for blackmail in 1972.
They threatened to kill Raymond's ex-wife, to blow up his place and to shoot him, National Archive papers show.
But in a bizarre series of phone calls Raymond turned the tables on the blackmailers, who were posing as IRA members in search of funds.
Raymond, the son of a Liverpool lorry driver, founded a huge pornographic empire which included magazines such as Mayfair and Men Only.
In 1958 he opened the only premises in the UK to stage live striptease shows, and later went on to acquire property in London's West End.
When he died in 2008, aged 82 and a virtual recluse, he was thought to be worth £650m.
During the blackmail attempt Raymond convinced the men to bring forward their plot to collect a £15,000 payment from him, but their conversations were being covertly recorded by the police.
In one call Raymond told them he had the money there and then and demanded he have the opportunity to hand it over right away.
In the third phone conversation recorded by police, Raymond answered the phone and complained: "I've been waiting since half past bloody six."
The man, who identified himself as Mr McGrath, but was thought to be White, said: "I must apologise."
'You're bluffing me'
Raymond went on: "You know, if we make a deal let's make a deal because I'm going away... you don't understand, I'm pissed, I'm drinking here by myself and you are driving me mad."
The voice replies: "Alright, alright."
But when Raymond is told to be in his office at 2pm the next day he says: "No, I'm sorry I cannot do this, you see, I think this, you are trying to bluff me... if you want the money I've got the money here, now, Mr McGrath."
The argument continues, with Raymond eventually saying: "You can stick a bomb wherever you want to. The money I have got... I cannot stand another bloody night like this..."
The man says: "We will not blow your place up, we will bloody shoot you."
Raymond, knowing the police are listening, says: "Well you can shoot me as well if you want to, you know, but this I cannot stand. I have got the money now, if you don't want it I am going to put it back in the bank and you can do whatever you want."
The man relents and agrees to send someone "in the next quarter of an hour".
The change of plan led to their arrests. Reid was jailed for three years and White for five.
The defendants were acquitted of attempting to blackmail Robert Guccione, owner of the Penthouse Club and magazine.