ITN was today preparing to fight an order from the Bloody Sunday tribunal that it should identify soldiers interviewed by Channel 4 News for a series of controversial reports on the 1972 killings of 13 civilians.
Channel 4 News presenter Mr Alex Thomson and his former producer Ms Lena Ferguson refused to reveal the names despite being warned by Inquiry chairman Lord Saville that they would be held in contempt.
They have 14 days to change their minds, but Mr Thomson said the principle that a journalist did not betray his sources was "absolutely fundamental".
He said: "It cannot be compromised and if it means serving a prison sentence to defend that principle, then that is precisely what I shall do."
Ms Ferguson, who now works for the BBC in Belfast, said she had given her word to the soldiers not to identify them and she was not prepared to go back on it.
ITN announced immediately after the ruling that they would launch an appeal.
The journalists interviewed five soldiers who were in Derry on Bloody Sunday - January 30 1972 - for a series of reports in 1997 which added to the pressure for a fresh inquiry into the Army's killing of 13 civilians on a civil rights march.
They were called to give evidence to the inquiry in Derry this week and refused to name their sources, although one of the five soldiers has since identified himself to the inquiry.
The order that they should - which they again defied - was made in a ruling by Lord Saville today following lengthy legal argument.
He had made a similar ruling in 1999 that ITN should reveal the names of the soldiers "if it cannot be obtained by other means".
Lord Saville said in his ruling today there was now little prospect of either the soldiers coming forward or the inquiry itself discovering who they are.
PA