The Bloody Sunday Inquiry/Day 327: The chairman of the Bloody Sunday inquiry yesterday refused to allow a barrister to question an MI5 officer about the extent of the security service's penetration of the Provisional IRA.
Lord Saville of Newdigate made his ruling when Mr Barry MacDonald QC was cross-examining a witness, known as Officer E, who during her career in MI5 analysed the quality of information on republican terrorism which was provided by informers.
Officer E told the inquiry that for a two-year period in the early 1990s she had worked in a security service section that was known as T2.
"I was responsible for - numbers varied - but about eight or 10 members of staff, all junior to me, who were investigative officers and at the time we were investigating Irish republican terrorism on the mainland, so I would supervise their work and manage their investigations."
Officer E said that during her posting to T2 she became aware of an informer codenamed Infliction - a former senior member of the Provisional IRA in Derry - who provided information on the IRA to MI5 for over 10 years.
Infliction, who was paid between £15,000 and £25,000 per year by MI5, told his handlers that Mr Martin McGuinness, of Sinn Féin, had fired the first shot on Bloody Sunday from a Thompson sub-machinegun.
He had also said that Mr McGuinness had been a member of the Provisional IRA's army council.
During his cross-examination of the witness, Mr MacDonald, who represents the families of most of the Bloody Sunday victims, suggested to Officer E that, in addition to Infliction, MI5 must have had other agents who were senior members of the IRA
"Does it go without saying there must have been very senior members of the IRA who were acting as agents of the security service?" he asked.
However, Mr Phillip Sales QC, who represents MI5, said he objected to Mr MacDonald's question.
"This is asking the witness to either speculate or give evidence from her knowledge about the extent of investigations carried out by the security service, and the sources available to them in investigating terrorism in Northern Ireland, and we would respectfully submit that this is precisely the area which cannot be gone into in public by the inquiry," he said.
Lord Saville said that Mr MacDonald's question could not be asked.
He added: "My immediate reaction is that, unfortunately, we cannot go down that path."
The inquiry resumes on Monday.