New Labour's good intentions in foreign policy have turned to "dust", former home secretary Charles Clarke has warned.
He said that despite Tony Blair's promises ten years ago, Britain was now isolated in Europe, had failed to live up to its moral posturing and had undermined its own commitment to nuclear non-proliferation.
"Despite its important international successes, the Blair premiership is a classic illustration of the potential for good intentions to turn to dust," Mr Clarke wrote in an article for the New Statesman.
"The Britain which was to be at 'the heart of Europe' has failed to face its Eurodemons and is now more remote from the centre of European power than ever.
"An 'ethical foreign policy' has given way to a desire not to rock the boat of arms sales to Saudi Arabia. And a commitment to nuclear non-proliferation has yielded to an overhasty and ill-considered determination to renew Trident, whatever the future security threats."
Mr Clarke, whose long-standing loyalty to the prime minister has been replaced in recent months with a series of public criticisms of New Labour, made his comments as the government sought to distance itself from US policy of sending more troops to Iraq.
There are growing calls for Britain to forge a separate policy from that of the White House, and Gordon Brown, who is expected to take over from Mr Blair when he resigns this summer, has promised a more "frank" relationship with the US.
But Mr Clarke warned that New Labour's failures were the responsibility of all ministers, saying: "These have been the approaches of the whole government, with the chancellor bearing as much responsibility as the prime minister - indeed, in some areas more."
Liberal Democrat foreign affairs spokesman Michael Moore said the former home secretary's comments were a "devastating critique" of New Labour's attempt to change its policy from that of the Conservatives.
"It also highlights how the prime minister has marginalised Britain's influence around the world," he said.
"Not before time the chancellor has talked of his ambition for an independent British foreign policy. We need to rebalance our foreign policy away from complete reliance on the United States to put ourselves in the European mainstream."
Responding to Lib Dem criticism of his close relationship with the US in the House of Commons yesterday, Mr Blair said: "The alliance of Britain with the United States of America, in my view, is in the British national interest, I think it is an important part of our foreign policy.
"I think there are two great relationships that Britain has in the world - one with America, the other with Europe - and we should maintain both and keep them strong."