London's former ambassador to Washington says the war in Iraq fuelled home-grown terrorism in Britain, in comments likely to cause further problems for Prime Minister Tony Blair at the end of turbulent political week.
Sir Christopher Meyer, who was heavily involved in the planning that led up to the war, said he disagreed with Blair's view that joining the United States in the 2003 invasion of Iraq had not exposed Britain to terrorist attacks.
Islamist suicide bombers killed 52 people in coordinated attacks on the London transport system four months ago.
"There is plenty of evidence around at the moment that home-grown terrorism was partly radicalised and fuelled by what is going on in Iraq," Sir Christopher told today's Guardiannewspaper in an interview ahead of publication of his memoirs.
"There is no way we can credibly get up and say it has nothing to do with it. Don't tell me that being in Iraq has got nothing to do with it. Of course it has," he said.
Sir Christopher, ambassador in Washington from 1997 to February 2003 but now retired from the diplomatic service, said he backed the invasion to topple Saddam Hussein in Baghdad and still felt the war was right in principle.
But he criticised how the aftermath was handled, telling the paper: "I don't believe the enterprise is doomed necessarily though, God, it does not look good. A lot of people think what we are going to end up with is precisely what we did not want."
Sir Christopher, currently chairman of Britain's Press Complaints Commission, said he opposed pulling US and British troops out early from Iraq but added: "I think the US and ourselves are on the horns of an absolutely impossible dilemma."
To abandon rebuilding of Iraq would leave "the relatives of at least 2,000 American servicemen and 98 British servicemen with a legitimate question about what they died for".
Meyer's damaging critique appeared on the front page of the newspaper alongside an interview with Mr Blair himself who conceded that his ruling Labour government faced a critical time.