The Bloody Sunday tribunal today ruled intelligence material directly relating to the activities of civilian witnesses on the day of the shootings should be admitted to the inquiry.
But Lord Justice Saville's team turned down an application from lawyers representing the Ministry of Defence that all material held by government intelligence agencies on witnesses' possible paramilitary activities which were unconnected with Bloody Sunday should be made available to the investigation.
This means if there is intelligence material that a civilian witness was in the IRA on Bloody Sunday, the team should be told.
However, if a witness joined the IRA after the event, this is irrelevant for the purposes of the inquiry.
Lord Saville and his two tribunal colleagues ruled that only "directly relevant material" would be sought from the intelligence agencies.
The tribunal said it wanted access to "material that would add to the inquiry's knowledge and understanding of the events of Bloody Sunday".
"In other words information that throws any light either on the plans made by any paramilitary organisation for Bloody Sunday or on the actual events of the day."
"It seems to us that in order to keep the matter within the limits of practicability, we should ask the agencies, at least in the first instance, to confine their search to the material in the files of those individuals identified to them by the inquiry, namely those individuals from or in respect of whom the inquiry has or expects to have some evidence about Bloody Sunday."
The ruling was made after a row broke out raising the prospect of some witnesses refusing to give evidence.
Rejecting applications by lawyers representing some of the civilian witnesses that even directly relevant intelligence material should not be sought, Lord Saville said it would be a "derogation of our duty to conduct as through an inquiry as possible" if the inquiry did not at least investigate and consider such material held by the intelligence agencies.
The fact that the team had asked for the production of directly relevant material did not indicate any partiality or lack of independence - merely a desire to explore all avenues of inquiry properly open to it, said the Saville panel. However it made clear its intention to safeguard individuals rights.
There would be no question of publishing or otherwise dealing with material so as to "prejudice possible rights of individuals, whether these arise under the Convention on Human Rights, or otherwise."
Lord Saville also ruled that it would not require the production of records of intercepted communications before the introduction of the Communications Act 1985, and only afterwards if it did not contravene the Regulation of Investigatory Powers Act 2000.
When the inquiry resumes next Monday, after a week-long break, Lord Saville will hear submissions from soldiers called by the inquiry to give evidence.
PA