The diverse group, including the musician Brian Eno, the actor and film director Mark Rylance and the guitar player John Williams, as well as 100 academics, MPs and activists, signed an open letter of protest condemning the continued occupation of Iraq as "an unmitigated disaster".
The letter, which was also signed by the film director Ken Loach, the Body Shop founder Anita Roddick and the poet Benjamin Zephaniah, urged Mr Blair to start moves to pull troops out of Iraq when the US-led alliance's United Nations mandate expires at the end of December.
Mr Eno and the film star Julie Christie delivered the letter to Downing Street yesterday, the day after a suicide bomber killed more than 150 in Baghdad's bloodiest day since the fall of Saddam. And in the past week, three more British soldiers have been killed in Iraq, bringing to 95 the number of British service personnel killed in there since March 2003.
The text states: "The war and occupation of Iraq have been an unmitigated disaster, both for the people of Iraq and Britain. Countless innocent Iraqis have lost their lives and still more innocents have been killed on our streets.
"British soldiers, many of whom do not want to serve in Iraq, have been killed, wounded or maimed."
The letter argues that a pullout would stop Iraqi deaths at the hands of British troops and make Britain's streets safer.
Speaking in Downing Street, Mr Eno told The Independent: "We are saying that the war is a disaster and has failed in every way and is continuing to fail. Personally I'm saying I do not want to be associated with a bunch of red necks with big guns and small minds.
"People who were perhaps agnostic about the war have become much more sceptical about it. I want to say to Mr Blair that he would not be that badly off if he admitted he had made the wrong decision." Ms Christie added: "What we are doing is encouraging the growth of terrorism, despite Tony Blair's vociferous denials.
"People will not stop fighting against occupation," Asked what her message was to Mr Blair, she said: "It's hard to talk to someone who isn't listening."
The letter was drawn up by the Stop the War coalition. The group is hoping for a huge turnout at a demonstration in London on 24 September, on the eve of the Labour Party conference.
Labour left-wingers are planning to raise the war at the conference, and are hoping for a significant demonstration to increase the pressure on Mr Blair to act. Jeremy Corbyn, the MP for Islington North, said campaigners were attempting to secure a debate on an emergency resolution on Iraq at Labour's conference later this month.
He said: "The message of the eve of the Labour Party conference will remind Tony Blair of the anger about the Iraq war. We want to ... build support for the march on September 24."
Other signatories include Professor Richard Dawkins, the scientist, Billy Bragg, Tony Woodley, the general secretary of the Transport and General Workers' Union and the playwright Harold Pinter.
The letter to the Prime Minister
The war and occupation of Iraq have been an unmitigated disaster both for the people of Iraq and Britain. Countless innocent Iraqis have lost their lives and still more innocents have been killed on our streets. British soldiers, many of whom do not want to serve in Iraq, have been killed, wounded or maimed.
The United Nations' mandate for the occupation of Iraq expires this December. We call on you to initiate the first steps to end this carnage by announcing that British troops will be brought home by the end of this year.
If you do this, you can stop the killing of any more Iraqis by British troops. You can save the lives of our soldiers. You can make Britain's streets safer. You can defend civil liberties rather than erode them.Reuse content