The journalist and author, Eamonn McCann, told the inquiry yesterday that he now believed that Mr Martin McGuinness of Sinn Fein was not the officer commanding the Provisional IRA in Derry at the time of Bloody Sunday.
Mr McCann confirmed in evidence that he has a belief as to who the OC of the Provisionals then was, but he said he was not willing to say who this was.
Counsel to the tribunal, Mr Christopher Clarke QC, began a detailed examination of Mr McCann in regard to sections of his book, War and an Irish Town, which was published in the 1970s and which describes the development of the Official and Provisional IRA movements in Derry.
Counsel noted that a passage in the book refers to "Martin McGuinness, the Provisionals' OC" as having proposed a call for a national strike until after the funerals of the Bloody Sunday victims. This was said to have taken place at a meeting in a shop in the Creggan on the evening of the shootings.
Counsel asked: "Can we take it that Martin McGuinness was known to be the officer commanding the Provisionals in this city on January 30th, 1972?"
Mr McCann replied: "That is the clear meaning of the passage. Actually I have to say that it is my belief now that Mr McGuinness was not the officer commanding the Provisionals in Derry at the time - that was a role widely ascribed to him and it was my belief at the time. I certainly could not prove that he was."
He added that he had no direct knowledge of what role Mr McGuinness might have played in the Provisional IRA, but it was widely believed that he was a prominent member. The witness said that when he wrote the book he had believed wrongly that Mr McGuinness was the OC. Asked by counsel who in fact was the OC, he replied: "I am not willing to say."
Earlier, Mr McCann was asked about a reference in his statement to the inquiry to there having been "plenty of loose talk about the IRA" in the Bogside and Creggan in the late 1970s. He said there were many people at that time who were identified or credited "or discredited" as members of either wing of the IRA.
In his statement, Mr McCann also said that he would have known a number of people in the Officials at the time, more than he would have known in the Provisionals. "It was easy enough for anybody at that time to talk to Official or Provisional IRA members about their strategy," he said.
Although he was not involved in the organisation of this march, he was in touch with leaders of the Official IRA, his statement added, "and I knew from them that the orders of the day on January 30th, 1972, were that its members would not be present carrying guns".
Counsel wrote on a piece of paper and handed it to the witness, asking him: "Is that the man you believe to have been head of the Officials?" Mr McCann said he was not willing to confirm this.
Counsel referred to a passage in Mr McCann's book which names three members of the Labour Party in Northern Ireland who were described as "moving towards the Officials" after internment was introduced. Counsel said that two of those named were persons who had made an application to this tribunal for anonymity.
He asked the witness if he would be prepared "to indicate whether the names on a list that I can show you include the names of the Labour Party members who joined the Officials on internment?"
Mr McCann said that he would not, and one of the reasons was the fact that some of these people were already speaking to tribunal lawyers and had expressed a willingness in principle to come forward and give their own evidence.
Counsel asked: "Is your position that you are not presently prepared to reveal to this tribunal, either openly or on a piece of paper, who were the Officials with whom you were familiar at the time of Bloody Sunday?"
Mr McCann said his position was that any information which came to him and which he had used in his journalistic work was confidential. "It would be unprincipled of me as a journalist to take any step which would reveal the identities of those people and I shall not do so," he said.
He said the name of Mr McGuinness was already in the public arena, so it would be meaningless to try to confer confidentiality on that, but this was not the case with some of the others.
Mr McCann also remarked that when he had referred to people joining the Officials, "please do not take that as meaning necessarily that they joined the Official IRA". He had commented earlier that the republican movement had included a political as well as a paramilitary face.
Counsel asked him to consider overnight whether what he had already written in his book had sufficiently put those names into the public domain as to entitle him to confirm "either in this chamber or on paper" the identity of the Officials to whom the book referred.
Mr McCann will continue his evidence today.