Prime Minister Gordon Brown has said the 2003 war was "right", as he gives evidence to the UK's Iraq inquiry.
He insisted he had not been kept in the dark by his predecessor Tony Blair and was fully "in line" with the invasion.
His own intelligence briefings had convinced him that Iraq was a threat that "had to be dealt with," he said.
But the main issue for him was that Iraq was in breach of UN resolutions - and that "rogue states" could not be allowed to flout international law.
If the international community could not act together over Iraq, Mr Brown said he feared the "new world order we were trying to create would be put at risk".
Summing up the two and half hour morning session, BBC Political Editor Nick Robinson said Mr Brown had repeatedly "spelt out his explanation of his own role often ignoring questions to the evident frustration of those asking".
"It was like watching a skilful chess player who had a defensive move prepared for every possible attack", he added.
Mr Brown, who was chancellor at the time of the war, is giving evidence weeks ahead of the UK general election, which is expected to be held in early May.
He began the session by paying tribute to the "sacrifice" made by British servicemen and women.
Friday, March 5, 2010
Prime Minster Gordon Brown: Iraq War Was The Right Call
Iraq inquiry: Gordon Brown says war was 'right'