A retired Garda detective has denied having any links to British intelligence.
John McCoy tried to claim privilege when he was questioned about former MI6 officer and whistle blower Fred Holyroyd - even though he said he did not know him.
John McCoy was giving evidence by video link from Dublin at the trial of prominent republican Gerry McGeough.
Mr McGeough denies attempting to murder a UDR soldier nearly 30 years ago.
The prosecution claims that Mr McGeough, 51, was injured after his intended victim Samuel Brush returned fire on him during an ambush near Aughnacloy in June 1981.
It is alleged that Mr McGeough from Carrycastle Road, Dungannon, who stood in the 2007 Assembly elections, was treated for a gunshot wound in a Dublin hospital before being transferred to Monaghan County Hospital.
Belfast Crown Court heard from John McCoy that he was one of the police officers assigned to guard a man he believed to be Mr McGeough but the patient walked out of the hospital along with a large group of visitors, including he claimed, leading IRA man Jim Lynagh.
During cross examination, a lawyer for Mr McGeough asked the retired detective if he knew a man called Fred Holyroyd.
He replied that he did not know him but said: "I would claim privilege on that".
Mr McCoy said he had read plenty of newspaper articles "that I have been associated with that particular gentleman but I cannot recall ever having met him."
'Protect the State'
The lawyer asked Mr McCoy: "Why did you ask to claim privilege in respect of someone you didn't know?"
McCoy replied "I didn't want to pursue it to protect the State".
He added: "My reputation has been linked to this man by numerous statements and articles in the papers and this gentleman said he knew me."
But he insisted he had never had any dealings with Mr Holyroyd.
Also in the dock was 47-year-old Vincent McAnespie from Aghabo Close, Aughnacloy.
He denies possession of guns and ammunition and impeding Mr McGeough's apprehension by hiding the weapons.