In a devastating verdict on Tony Blair’s decision to back war in Iraq and his “totally one-sided” relationship with President Bush, a US State Department official has said that Britain’s role as a bridge between America and Europe is now “disappearing before our eyes”.

Kendall Myers, a senior State Department analyst, disclosed that for all Britain’s attempts to influence US policy in recent years, “we typically ignore them and take no notice — it’s a sad business”.

He added that he felt “a little ashamed” at Mr Bush’s treatment of the Prime Minister, who had invested so much of his political capital in standing shoulder to shoulder with America after 9/11.

Speaking at an academic forum in Washington on Tuesday night, he answered a question from The Times, saying: “It was a done deal from the beginning, it was a onesided relationship that was entered into with open eyes . . . there was nothing. There was no payback, no sense of reciprocity.”

His remarks brought calls from British politicians last night for the special relationship to be rethought, but also attracted scathing criticism from one close supporter of the Prime Minister.

Dr Myers had hard words for his own Administration’s record in the Iraq war: “It’s a bad time, let’s face it. We have not only failed to do what we wanted to do in Iraq but we have greatly strained our relationship with [Britain].”

Dr Myers, a specialist in British politics, predicted that the tight bond between Mr Bush and Mr Blair would not be replicated in the future. “What I think and fear is that Britain will draw back from the US without moving closer to Europe. In that sense London’s bridge is falling down.”

The extraordinarily frank remarks will be seen as further evidence of the long-standing unease felt within some parts of the State Department over the direction of White House policy. They may also be an indication of the weakness of President Bush as he struggles to stop Iraq sliding into civil war and faces a Democrat-dominated Congress elected this month.

Sir Menzies Campbell, the Liberal Democrat leader, said: “These remarks reflect a real sense of distaste among thinking Americans for Mr Blair’s apparent slavish support for President Bush . . . The special relationship needs to be rebalanced, rethought and renewed.”

But Denis MacShane, Labour MP for Rotherham and a former Foreign Office minister, who supported the Iraq war, said: “After the Republican defeat in the midterm election, every little rat who feasted during the Bush years is now leaving the ship. I would respect this gentleman, who I have never heard of, if he had had the guts to make any of these points two or five years ago.”

Last night Dr Myers, who is thought to have attended the discussions over the infamous Downing Street memo in 2002 before the Iraq war, was disowned by the State Department. Terry Davidson, a spokesman, said: “The US-UK relationship is indeed a special one. The US and the UK work together, along with our allies in Europe and across the world, on every issue imaginable. The views expressed by Mr Myers do not represent the views of the US Government. He was speaking as an academic, not as a representative of the State Department.”

Privately, US officials are furious about the comments made by a man not even involved in the policymaking process, which can only rock relations at a time of high-wire tension in international diplomacy. Dr Myers himself was said to be considering early retirement.

He said on Tuesday that Mr Blair had been left “ruined for all time” by the Iraq war and that if he had “only read a book” on the last British invasion of Iraq in the 1920s, “he might have hesitated”.

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