Britain’s longest serving IRA prisoner tried to cover up a blackmail plot, a court has been told.

Described as a ‘celebrity’ in |Republican circles, Ronald McCartney’s explanation for his role in the alleged conspiracy to extort six-figure sums from two businessmen was dismissed as ‘just rubbish’ by the prosecution.

McCartney (55), from Ross Road, Belfast, told London’s Southwark Crown Court that far from being financially motivated, his actions were, in fact, part of a “sophisticated and convoluted” scheme to protect delicate |negotiations between Sinn Fein and the Democratic Union Party.

In the dock with him are Nick Mullen (60), another former IRA prisoner, of Burlington Mews, West Acton, west London, and Louis O’Hara (43), of Collard |Avenue, Loughton, Essex.

All three deny deny two counts of conspiracy to blackmail between January 1 and April 16, 2008.

Mark Heywood, prosecuting, told jurors McCartney was not a “trustworthy witness” because he “lied through your teeth” during a police interview in which he |declined legal representation.

He said: “From your very first contact with the police you set out to lie. Do you think it shows a sort of arrogance that you thought you could get it past the police?”

McCartney, who was jailed in the seventies for attempting to murder three policemen in Southampton, replied: “I’m not an arrogant person. I lied because of my psychological state of mind — I thought my life was f*****.

“I thought about my wife and the shame I brought on the Republican movement, it was panic.”

The defendant, who yesterday admitted he was suffering a drink problem, maintained he was not pursuing a personal fortune and said that if the alleged victims had agreed to pay the money he would not have accepted it.

He explained: “I would have refused it immediately because this is not about money, it’s about resolving a situation.”

“The whole purpose of me writing that letter would have failed if they agreed to pay because the Republican movement would not have become involved and in my mind they were the only people who could resolve this situation.”

The Crown claimed McCartney initially lied to police about his |address, an allegedly incriminating business card he dropped at the police station, and told further falsehoods when denying making phone calls to the businessmen.

Raising his voice, McCartney said: “Excuse me, I was in a situation where my life was destroyed. I told lies ... I did not expect the |policemen to understand what I was trying to do.”

The trial was adjourned until Monday.