The Foreign Office’s top civil servant, Sir Michael Jay, warned in May 2004 the war was fuelling UK Muslim extremism.

Responding for the first time to leaks of the warning, Mr Straw said he had agreed Sir Michael’s letter.

He said extremists used the war as an “excuse” but that did not mean the UK would have been safer without it.

“We were in any event a target, and so was the rest of the world, for this extremist terrorism before Iraq,” he said.

He denied any suggestion that the UK would somehow have been immune from attack if the war had not happened.

‘Inept’

Mr Straw said Sir Michael’s letter, leaked to The Observer newspaper this weekend, echoed his own comments at the time.

Sir Michael, writing to Cabinet Secretary Sir Andrew Turnbull, said British foreign policy was a “key driver” behind recruitment by extremist Muslim groups.

At best, the constitution will lead to peace and tranquillity Jack Straw Foreign Secretary

Sir Michael Jay’s letter last May said a “recurring theme” among the underlying causes of extremism in the Muslim community was “the issue of British foreign policy, especially in the context of the Middle East peace process and Iraq”.

It added: “British foreign policy and the perception of its negative effect on Muslims globally plays a role in creating a feeling of anger and impotence among especially the younger of British Muslims.”

Shadow foreign secretary Liam Fox told BBC News the government’s handling of the problem had been “inept from start to finish”.

“What I find surprising is that the government denies there is any link when most people, with common sense, would say there is some link that makes it easier to recruit extremists from the Muslim community,” he said.

Liberal Democrat foreign affairs spokesman Menzies Campbell said: “It may well be that there wasn’t very much the government could do.

“But I think it’s an indication of the fact that the reasons for the terrible events of 7 July, and the apparent attempt to recreate these events on the 21 July, are very complex indeed and it’s not simply a question of competing ideologies as the prime minister would argue.”

hopes

Meanwhile, the final draft of the new Iraqi constitution was read to the Iraq assembly on Sunday.

Negotiators representing Iraq’s Sunni minority have rejected the document and urged the United Nations and Arab league to intervene.

The Iraqi people will decide in a referendum, scheduled to take place by mid-October, whether to accept the draft constitution.

Mr Straw said he had hoped the document would be accepted by all groups in Iraq but there had always been arguments in the long history of drawing up constitutions worldwide.

He said it was impressive that elected representatives from 80% of the community in Iraq - the Shia and Kurds - had largely supported the document.

And not all Sunni Iraqis opposed the constitution, he said.

“At best, it will lead to peace and tranquillity,” he argued.

Mr Straw stressed that the constitution process was endorsed by the United Nations as a whole and not just the brainchild of the UK and US.

The foreign secretary admitted the coalition had not got everything right in the aftermath of the Iraq invasion.

“One of the things we didn’t predict was the speed with which the Saddam regime would collapse,” he said.

But he argued the decisions taken had been “overwhelmingly more right than wrong”, although the extent of violence in Iraq could not be blamed completely on the way Iraq was governed under Saddam Hussein.