The Saville Inquiry into Bloody Sunday was halted today by last-minute bids for screening by police witnesses.
The move, by an unknown number of former RUC officers, meant the hearings were put off until Thursday for a special hearing into their application.
It followed the first live man testimony from a police witness, Mr William George Hunter, a Special Branch officer whose evidence at the Guildhall in Derry was accompanied by tight security because of a screening order.
He sat inside a high-sided witness box, visible only to Lord Saville and his fellow judges on the tribunal and lawyers representing the victims and soldiers involved in the killings.
Mr Hunter had won the right to conceal his face at the inquiry in an application made in June 2000 but most other officers were - until today - expected to be unscreened before the public hearings into the killings of 13 Catholics on January 30th, 1972.
Lord Saville said: "The application has come in very late and that has meant a complete disruption to our timetable for this week."
He added later: "What is important is that all the police officers who are shortly to give evidence before this inquiry should make sure that if they want to make an application for screening ... now is the time for them to do so because we simply cannot afford to waste time with people turning up with applications at the last minute, thereby causing us to lose days of witness time.
Michael McKinney, whose brother William (26) was killed on Bloody Sunday said he was dismayed by the new bids for screening. "Why would they wait until the last minute when this application could have been made before?" he asked. "It's stalling tactics. What else can it be."
Earlier, the inquiry heard Mr Hunter defend his claim that he heard between six and 10 nail bombs explode and a Thompson sub-machine gun - an IRA weapon - ring out before he heard British army gunfire that day - supporting the claims of troops.
Mr Hunter claimed to have heard the noises after paratroopers moved into the Bogside in the aftermath of the civil rights march taking place that day on what was supposed to be an arrest operation.
He said he was standing behind army lines on William Street with two colleagues with the brief of looking out for known troublemakers, republican activists and terrorists who may have infiltrated the march.
Mr Hunter said he did not see any IRA personnel, republican activists or known troublemakers taking part in the march, although he said his knowledge of such people was "limited".
He said he did not report the sounds of explosions and gunfire through the RUC radio system - the RUC radio log for Bloody Sunday contained no record of them - but he maintained that that did not mean it had not happened.
Mr Hunter was also shown the reports written by his two Special Branch colleagues who had been beside him at the time, which recorded the same details, but he maintained: "I made my report in Castlereagh and I was not subject to coercion of any sort."
Michael Mansfield QC, acting for the relatives of Barney McGuigan, William Nash and Alexander Nash, said no nail bombs had been recovered from the area where Mr Hunter claimed they must have exploded, nor did photographic evidence back his claims up.
He accused Mr Hunter of "not being completely frank" about what he had seen and heard, to which Mr Hunter replied: "I can assure you I am being completely frank."
Mr Hunter also told the hearing that he saw Major General Robert Ford - the army's second-in-command in Northern Ireland at the time - in the same area of William Street for most of the day and noted: "He appeared to be in charge of the situation."
Major General Ford has always maintained he was present that day only as an observer.
PA