The Bloody Sunday Inquiry in Derry was today preparing for its first hearing of the New Year with a question mark hanging over its future.
Before Christmas the British home secretary, Mr Jack Straw and defence secretary, Mr Geoff Hoon, submitted public interest immunity certificates which would restrict publication of material about two security service agents and their handlers.
Restrictions on intelligence sources have been resisted by lawyers acting for relatives of those who died. Inquiry chairman Lord Saville asked what Westminster would do if it felt that an effective investigation could not be carried out.
Counsel to the inquiry, Mr Christopher Clarke QC, said if this was this case, parliament might have to "square the circle" and decide the inquiry should stop.
The inquiry must also rule on the evidence given by an intelligence agent codenamed "Infliction" and on the anonymity of army witnesss, Soldier B.
Former MI5 intelligence officer Mr David Shayler yesterday queried the reliability of evidence from "Infliction" who had alleged Mr Martin McGuinness had fired the first shot on Bloody Sunday at the British army.
Mr Shayler claimed in the Observer newspaper information from "Infliction" about the IRA was initially taken seriously by MI5 agents but was later found to be inaccurate. Mr Shayler queried why evidence from Infliction was being used at the Bloody Sunday Inquiry.
Civilian witnesses are to resume giving evidence to the inquiry today.