The Saville inquiry has to decide whether to order Channel Four to give it the names of soldiers interviewed for a series of reports in the late 1990s about the day troops shot dead 13 civilians in Derry.
Two Channel Four journalists have been called to the inquiry into Bloody Sunday in Derry to be asked to name five soldiers they interviewed.
So far, the journalists have refused and have indicated they will continue to do so because they made confidentiality agreements with the soldiers. Mr Alex Thompson and producer Ms Lena Ferguson could be declared in contempt of the inquiry and face jail.
Before Ms Ferguson gave evidence today, Mr Christopher Clarke, QC to the inquiry, said it was not possible to delay indefinitely the decision as to whether the identities should be revealed.
It was necessary to obtain evidence from the soldiers because some of what they said "goes to the heart of the issues the tribunal has to resolve," said Mr Clarke.
He said it was unlikely the soldiers would come forward themselves or their identities be discovered during the hearing of evidence from military witnesses later this year.
The tribunal had earlier asked ITN to contact the five soldiers, known as Soldiers A - E, and ask them if they would release it from the obligation of confidence or alternatively to contact the tribunal themselves.
Mr Clarke said Ms Ferguson was able to contact only three of the soldiers, A, B and D and they were not prepared to release ITN from their undertakings.
PA