Miliband: We would still have invaded Iraq with Gordon Brown in command

Gordon Brown's doctrine of "hard-headed internationalism" would have made no difference to Britain's decision to go to war with the US in Iraq, the Foreign Secretary David Miliband admitted yesterday.

The Prime Minister's strategy for foreign affairs, outlined in his speech at the Lord Mayor of London's Banquet on Monday, was seen as an attempt to draw a line under the Blair years, when Tony Blair was accused of being too close to the foreign policy aims of the US President George Bush.

However, Mr Miliband said the Brown strategy would not have stopped Britain going to war. Asked on BBC Radio whether the same decision would have been made under Mr Brown's doctrine, Mr Miliband replied: "In respect of the decision to invade Iraq, absolutely right." He conceded that decisions taken since the war "could have been done better" but insisted: "No one is resiling from the original decision."

Mr Miliband's remarks will disappoint Labour MPs who opposed the war and believed that the transfer of power to Mr Brown would herald a foreign policy shift that would rule out pre-emptive intervention in future without the backing of the United Nations.

Later, Mr Miliband also warned that Mr Brown could lose the next general election unless the Government was seen to be effective and competent. That was seen as a signal to No 10 that it has to "raise its game" following blunders over the timing of the general election, the retreat over capital gains tax, the Northern Rock fiasco and the row over the leaked Home Office memorandum on illegal immigrants. "The next election is Labour's to lose and not the Tories to win," Mr Miliband said, adding that it would be the Government's decisions that would reveal its competence, and its vision in office. "I believe if we are both a competent and effective Government, we will be in a very strong position in the next general election," he said.

Mr Miliband was seen by some MPs as a natural heir to Mr Blair and touted as a possible leadership candidate until he made it clear he would not run against Mr Brown. His warning echoes the view held by many Labour backbenchers that they have to keep their nerve but improve the Government's performance.

The Foreign Secretary said the Government had to show it had "learnt the lessons" of being in power for a decade, adding: "I believe the way in which we will get credit for Labour's record is by showing we have learnt the lessons of what did not go so well."

Mr Miliband will shortly visit the Middle East as part of a drive to reach a lasting peace settlement over the Palestinian question.