Northern Ireland Deputy First Minister Martin McGuinness was involved in approving the IRA ambush in which two senior RUC officers were killed, it has been claimed at the Smithwick Tribunal.
Ian Hurst, a former British army intelligence officer, made the claim in his evidence to the tribunal last week behind closed doors.
Today his evidence is being read into the record.
Mr Hurst also made allegations linking two former gardaí to the IRA and claimed that Freddie Scappaticci was the highly prized British army agent within the IRA known as Stakeknife.
The two former officers, Owen Corrigan and Leo Colton, as well as Mr Scappaticci have denied the allegations.
Mr Hurst said he was told by his superior officer, known to the tribunal as Witness 82, that as Officer Commanding the Northern Command Mr McGuinness had to approve the operation because it would have needed between 30 and 60 members to carry out the operation.
An operation of this type would have needed ''political cover'' and the witness said he believed the aim was to kidnap, interrogate using extreme violence and extract intelligence from the two RUC men.
Chief Supt Harry Breen and Supt Bob Buchanan were the most senior RUC officers to die in the Troubles.
They died minutes after leaving a meeting in Dundalk Garda Station in March 1989.
The Smithwick Tribunal is investigating claims that gardaí colluded with the IRA in providing information allowing them to set up the ambush.
Mr Hurst also claimed that Freddie Scappaticci was the British army agent known as Stakeknife.
He told the tribunal he was on duty one night when the phone in the FRU office rang and it was a policeman.
That man said Mr Scappaticci had told him to ring this number and the caller said he wanted to know who was on the other end.
Mr Hurst said his senior officers sorted the issue out. The following day he was interviewed about the contact and that had never happened before.
The witness said he then went "nosing about" and discovered that Mr Scappaticci was as senior officer in the IRA's internal security unit.
During his time in the FRU, Mr Hurst said he saw about ten intelligence reports called MISRs which said that Owen Corrigan was a garda passing information to the IRA.
There were some reports mentioning Leo Colton but not as many as mentioned Mr Corrigan.
The witness was pressed as to how he could remember these two names among the thousands of intelligence reports he saw.
Mr Hurst said he did so because they were unusual names and they were rogue gardaí.
He said he discussed Mr Corrigan with his superior officer, known as Witness 82, two or three times.
Witness 82, who was Stakeknife's handler, told him that Mr Scappaticci was ''running'' Mr Corrigan and getting information from him but that is a claim which is disputed by Witness 82.
The witness also said Mr Scappaticci was a member of the IRA's Northern Command.
Mr Hurst said Dundalk, Ballyhsannon and Bundoran were not highly thought of by British military intelligence as many IRA members went there to rest and relax before returning to the North and they were places where a lot of interrogations took place.
Dundalk, he said, was viewed as "a rat infested hole."
Mr Hurst worked for the secretive British Army's Force Research Unit in Northern Ireland for several years.
He worked as an agent handler and collator.
His appearance before the tribunal had to be agreed with the British Ministry of Defence as the witness is subject to orders preventing him speaking in public.
He said the FRU worked on a 32-county basis and collected intelligence from the Republic, as well as the North.
They were forbidden from recruiting agents in the loyalist community because the RUC did not want them to discover their "corrupt practices".
The witness said when he decided to get married to a woman from the Republic he left the army.
He said they were living in Carrick-on-Suir when his house was broken into.
The manuscript of a book he was writing was stolen.
That manuscript later appeared in the High Court in London when the Ministry of Defence sought to get an injunction against him.
Under cross-examination by Jim O'Callaghan, counsel for Owen Corrigan, the witness denied that he was lying, making things up as he went along or that he was a "spoofer."
It was put to Mr Hurst that Witness 82 would not back up his claims about Mr Corrigan was passing information to Mr Scappaticci, the witness said that as his former handler he would have been aware of criminal activity being carried out by his agent.
Mr O'Callaghan pointed out that in his 27-page statement he never once mentioned his allegation that Mr Corrigan was passing information.
It was also pointed out that he had said initially there were no intelligence reports which linked gardaí to the killings of the two senior RUC officers but now he was claiming it did exist.
Mr Hurst also gave evidence into the Saville Inquiry into the events of Bloody Sunday and Mr O'Callaghan pointed out that Judge Saville found that "to a substantial degree he exaggerated the importance of his role and level of knowledge and access to intelligence.''
However, Mr Hurst said that the judge was wrong in his assessment.
