I have nothing to hide over murders says McGuinness

But the Sinn Fein MP insisted he would have nothing to contribute to the Smithwick inquiry in Dublin because he has no knowledge of the incident.

Mr McGuinness said: “I made it clear some time ago if there was a need for me to (attend), I would be prepared.

“But I thought I had absolutely no contribution to make whatsoever. It’s an incident I know absolutely nothing about.”

British intelligence officer Ian Hurst – also known as Martin Ingram –- claimed at the inquiry this week to have inside knowledge linking the Sinn Fein chief to an order for the 1989 border ambush of Chief Superintendent Harry Breen and Superintendent Bob Buchanan.

Mr McGuinness dismissed the evidence against him read into the record at the tribunal as nothing more than “a yarn”.

“I’ve totally and absolutely refuted and rejected what turned out to be a yarn, a cock-and-bull story given to the Smithwick Tribunal by a man initially named as Hurst.”

He described the witness as a fantasist.

The inquiry into IRA-garda collusion was told Mr McGuinness was in the IRA’s northern command and “involved” when terror chiefs sanctioned the double murders on their way home from a cross-border policing briefing.

Ingram, as he was known outside intelligence circles, told the inquiry that intelligence on the Buchanan and Breen atrocity came from the high-level double agent in the IRA known as Stakeknife, allegedly notorious Belfast republican Freddie Scappaticci.

Mr McGuinness a self-confessed Provisional IRA commander in Londonderry in the early 1970s, addressed the allegations publicly for the first time as he attended a conference in Dublin examining the experience of the Northern Ireland peace process.

He said he was confident that Mr Ingram would be discredited and that Judge Peter Smithwick would refuse to accept the evidence.

It would not be the Deputy First Minister’s first appearance at a major tribunal after he gave evidence at the Saville Tribunal – an inquiry into the 1972 Bloody Sunday massacre in which 14 civilians were shot dead by British soldiers in Derry. He said a witness, whom he described as similar to an intelligence officer who testified at Smithwick, also tried to discredit him, with allegations that were not accepted.

Meanwhile, First Minister Peter Robinson insisted that anyone making allegations should bring evidence to support them.

He said it was unsurprising that accusations have been made against Mr McGuinness given his past links with the IRA.

He added: “If there is firm evidence that someone has been involved in illegal activity then that’s a different matter and should be put to the courts.”

Earlier this week, a spokesman for Mr McGuinness, a self-confessed Provisional IRA commander in Londonderry in the early 1970s, described Mr Ingram as a dubious character and claimed the tribunal had questioned other British intelligence evidence.

Mr Ingram was a member of the British Army’s covert Force Research Unit (FRU) in Northern Ireland which itself has faced damning allegations of collusion, for gun-running with Loyalist paramilitaries and more than a dozen murders.

But his evidence prompted renewed questions over when Mr McGuinness stood down as a Provo commander. During his failed bid for the Irish presidency last autumn he repeatedly insisted it was 1974.