Britain must not turn its back on the world as a result of the controversy over the Iraq war, Foreign Secretary David Miliband said today.
Mr Miliband told the Chilcot Inquiry it was important not to learn the "wrong lesson" from the conflict and to decide to leave international engagement to other countries.
He also argued that the authority of the United Nations would have been badly damaged if the UK and the US had not followed through threats to Saddam Hussein with military action.
The Foreign Secretary admitted that the March 2003 invasion of Iraq exposed "divisions" in the international community.
But he insisted the UN would have been damaged if the conflict had not gone ahead.
Mr Miliband told the inquiry: "I think it's very important that we don't learn the wrong lesson, and the wrong lesson, it seems to me, is that Britain should leave international engagement to others, that the world is just so complicated and so dangerous that we are better off retreating into ourselves.
"There is an argument about whether or not medium-sized countries should think of themselves as global players.
"And I think it's going to be an argument that is more and more pressing in the months and years ahead because of the temptations for politicians - never mind those concerned with the finances - to rein us in."
He added: "We mustn't be a country that turns our back on the world because if we do, because of the hard decisions that we are faced with, we will be much poorer in all senses of that term."
Mr Miliband told the inquiry he voted for the invasion of Iraq in the Commons because Saddam's defiance of the UN posed a danger to global peace and security.
He said: "The authority of the UN, I think, would have been severely dented if the hypothetical case that you are putting - that we had marched to the top of the hill of pressure and then walked down again without disarming Saddam - then I think that would have been really quite damaging for any of the multilateral aims that we have that need to be pursued through the UN."
He added: "One of the striking points of the time is that the longer the UN fails to impose its will, the harsher the measures required when it finally does impose its will."
Britain and the US failed to get a second UN Security Council resolution directly authorising the invasion of Iraq, splitting the international community and leading critics to argue that the war was illegal.
Mr Miliband admitted: "Divisions in the UN were exposed by the run-up to the vote and then the absence of a vote (on taking military action against Saddam), and then divisions in Europe were exposed and divisions in the Western alliance were exposed."
But he said "all the intelligence agencies of the world" thought the Iraqi dictator had weapons material that posed a danger to international security.
The Foreign Secretary rejected claims that the overthrow of the Iraqi regime in 2003 freed up Iran to back militant groups and destabilise the Middle East.
"I don't buy the thesis that the removal of Saddam released Iran to do its ill around the region," he said.
Mr Miliband also argued that the murders of at least three out of five British contractors seized in Baghdad in May 2007 should not alter how the UK handles kidnappings.
He said: "We have a very, very clear policy that we will not make substantive concessions to hostage-takers, and I don't think that any lesson of this affair should be that we should change that policy."
Adjourning the inquiry's public sessions in central London until after the general election, chairman Sir John Chilcot issued a warning to politicians.
He said: "The Iraq Inquiry intends to remain out of the public eye over the period of the election.
"Because we are independent and non-political, we have been clear from the outset that we have to remain outside party politics and we have asked the political parties to respect that position.
"I would like to repeat that request as the election campaign comes closer."