Gordon Brown: Military action in Iraq was "the right decision... for the right reasons"
Gordon Brown has told the Iraq inquiry the war had been "right" - and troops had all the equipment they needed.
The PM also insisted he had not been kept in the dark by Tony Blair despite not being aware of some developments.
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".
Assessing the prime minister's four hour appearance before the committee, BBC Political Editor Nick Robinson said: "Gordon Brown's aim today appears to be to look and sound different from Tony Blair whilst simultaneously opening up no gap of substance with him and the decisions he took."
Mr Brown, who was chancellor at the time of the war, was giving evidence weeks ahead of the UK general election, which is expected to be held in early May.
THE STORY SO FAR
He may have been writing the cheques as chancellor, but Gordon Brown remained largely silent in the run-up to the 2003 Iraq war
He was thought by some to be sceptical about it. Others thought he was hedging his bets ahead of a leadership bid
After becoming PM, he set up the Iraq inquiry to "learn lessons" from the war, although he originally wanted it held in secret and the timing ensured it would not report until after the election
Ex-military leaders have given evidence at the inquiry suggesting Mr Brown kept defence spending tight during his 10 years at the Treasury with some suggesting this had a knock-on effect on forces' kit
Mr Brown has denied this and will want to counter any impression, as put by David Cameron, that he did not see the military as a priority until he was PM and it became politically convenient
He began the session by paying tribute to the "sacrifice" made by British servicemen and women, but he added: "I think it was the right decision and made for the right reasons."
Mr Brown acknowledged that there were "important lessons" to be learned from the way Iraq descended into chaos following the invasion.
"It was one of my regrets that I wasn't able to be more successful in pushing the Americans on this issue - that the planning for reconstruction was essential, just the same as planning for the war," he said.
And he added: "There will be other states, rogue states, that need to change and we need to ensure civilian support as well as military support to do what's necessary when a broken state has to be rebuilt."
He also stressed that he had always believed in an international effort to rebuild Iraq and create a "just peace" for its citizens, adding, in an apparent swipe at members of George Bush's US administration: "I never subscribed to what you might call the neo-Conservative position that somehow, at the barrel of a gun, overnight, liberty and democracy could be conjured up."
Setting out his thinking on the rationale for war for the first time in public, Mr Brown said terrorists and "rogue states" were the "two risks to the post-Cold War world" and had to be tackled.
He said he had met the intelligence service five times during 2002 and early 2003 and was given information "which led me to believe that Iraq was a threat that had to be dealt with by the actions of the international community."
But he added: "Right up to the last minute, right up to the last weekend, I think many of us were hopeful that the diplomatic route would succeed."
Mr Brown said he had largely restricted his involvement in the run up to war to financial matters, and he had assured Tony Blair at an early stage that he would not try to block military options "on the grounds of cost".
And he insisted UK forces had been given all the equipment they had asked for - in response to earlier evidence from ex-military leaders who told the inquiry spending had been squeezed.
"At any point, commanders were able to ask for equipment that they needed and I know of no occasion when they were turned down," he told the panel.
He said the total cost to the UK of the wars in Iraq and Afghanistan had been £18bn, in addition to a "rising" defence budget, which he admitted was a "sizeable sum of money" which had "made my life more difficult" as chancellor.
But he said the government had been able to meet the costs from reserves without making cuts elsewhere and it had ultimately been "manageable".
Georgina Pattinson, Assistant Editor BBC Democracy Live, at the Iraq inquiry
There was barely a sound in the inquiry room, particularly at moments when Mr Brown replied to key questions.
At the mention of those who lost their lives in the Iraq conflict, or on questions concerning the equipment given to the military, you could have heard a pin drop. There was a real feeling of tension, as those listening appeared to hold their breath.
But there were moments of lethargy among the audience too. When the prime minister began to answer questions with a long list of figures, there were some eyelids closing and heads nodding.
"Pretty stage-managed," said one member of the audience in the lift, leaving at the end of the two hour session.
"Not as stage-managed as Tony Blair," said another.
"That was pure theatre."
Panel member Lawrence Freedman challenged Mr Brown over funding for armed forces equipment - particularly Snatch Land Rovers, an issue he said had been raised by the families of soldiers killed in Iraq.
Mr Brown said Bulldog and Mastiff vehicles had been supplied to troops at a cost of £90m as soon as their commanders on the ground had asked for them, with the first of them arriving in Iraq "within six months".
Mr Brown praised Tony Blair's handling of the diplomatic negotiations: "Everything Mr Blair did, he did properly and I was kept fully informed about the information that I needed to make my decisions."
But he said he had largely restricted his involvement to financial matters, telling the inquiry: "My role in this was not to interfere in what were very important diplomatic negotiations."
He said he had not seen letters sent by Tony Blair to US President George W Bush - and had not been aware that Attorney General Lord Goldsmith had changed his opinion on the legality of the war.
Asked whether he knew what Mr Blair had said to Mr Bush at a private meeting at the US president's Texas ranch in 2002, at which some inquiry witnesses have suggested Mr Blair committed Britain to war, he said: "I didn't know the exact conversation and you wouldn't expect me to."
But he said the "decision making structures" at the top of the British government in the run up to war had been too informal and both he and Tony Blair had since taken steps to rectify this.
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.