The Bloody Sunday Inquiry will be delayed because one of its three members has resigned. It was due to resume next month.
The 71-year-old former New Zealand judge, Sir Edward Somers, said he felt he did not possess the necessary "vigour and energy" to meet the demands of the task.
It has also emerged that the inquiry, which was established by the British Prime Minister, Mr Blair, in January 1998 but only began its main oral hearings in Derry in March, has to date cost almost £25.6 million.
The East Derry Ulster Unionist Party MP, Mr William Ross, described the British government's continuing commitment to the inquiry as "scandalous".
Sir Edward, who will be 72 next month, announced with the "greatest regret" yesterday his withdrawal from the inquiry. He indicated that the demands of the investigation, which could last another two or three years, would be too taxing for him.
"I have, however, concluded that I shall not be able to bring to the task the vigour and energy which it will undoubtedly require over the remaining two to three years of its life," he explained.
The British government must now find a replacement for the retired judge, to join the inquiry chairman, Lord Saville of Newdigate, and Mr William Hoyt from Canada. His successor, who is expected to be drawn from the Commonwealth, must become familiarised with a huge amount of detailed information already presented.
The Bloody Sunday Inquiry admitted that this would delay proceedings for an unspecified period. "Given the volume of material with which any new member will have to familiarise him- or herself, the resumption of the oral hearings, previously scheduled for September 4th, 2000, will now be delayed by some weeks," a spokesman said yesterday.
The inquiry had been due to resume with a review of new evidence gathered during the summer recess. This was to have been delivered by Mr Christopher Clarke, QC to the tribunal, and was expected to have lasted one week followed by the opening statements of the interested parties.
While most relatives of the Bloody Sunday victims seemed sanguine about Sir Edward's resignation, they expressed some concern about the calibre of his replacement and the emotional effects the delay would have on them.
Mr Liam Wray, whose brother Jim was shot dead on Bloody Sunday in 1972, said the delay would put extra pressure on the families of the victims. "It has already taken quite a toll on the families since the inquiry was set up 2 1/2 years ago," he said.
"Most of us thought then that it would be over by now. I do respect Edward Somers's courage in making this decision for personal reasons, but it leaves us with a lot of problems. For example, how long will it take to appoint a new judge, will the new judge be acceptable and how long will it take the new judge to get up to scratch in terms of the inquiry?"
Mr Des Doherty, the solicitor who represents the family of one Bloody Sunday victim, Mr Barney McGuigan, said Sir Edward's decision could cause havoc for everyone involved in the inquiry.
"I spoke to Mrs McGuigan today and she is greatly disappointed. It will delay the start of the hearing and the only people who will benefit from this delay will be the military. The new judge will have to be an acceptable compromise to all the parties involved."