Britain tried to stop the US disbanding the army in Iraq after the fall of Saddam Hussein's regime, Europe minister Geoff Hoon has said.
Mr Hoon says Britain did not want to disband the Iraqi army
In an interview with the Daily Telegraph, Mr Hoon says British ministers "lost the argument".
His comments come after a senior US official described the relationship between the British and American governments as "totally one-sided".
Downing Street said the two countries had "a very close" relationship.
Mr Hoon, who was defence secretary at the time, said he and other members of the government tried to persuade the United States not to purge members of Saddam's Ba'ath party from senior positions in the army.
He told the Daily Telegraph: "We would not have disbanded the Iraqi army.
"We were very concerned in the final stages of the conflict that the Iraqi army was a force for stability in Iraq and I think we would have preferred for that army to remain intact."
He added: "I don't think we would have pursued the de-Ba'athification policy in quite the same way.
"I think we understood from perhaps experience in Europe that quite a lot of people were Ba'athists because they had to be if they wanted to be teachers or administrators and they weren't necessarily committed to Saddam Hussein.
"Those were arguments that I certainly put forward and I know other members of the government put forward. So we lost the argument."
Last month, Kendall Myers, a senior analyst at the US State Department, said Britain's relationship with America was "one-sided" and Prime Minister Tony Blair was routinely ignored by President George Bush.
He described Britain's attempts to influence US policy as a "sad business", the Times reported.
Liberal Democrat leader Sir Menzies Campbell said it was clear from early in the conflict that British advice was being ignored.
"The prime minister's strategy of staying close in public so as to be influential in private simply didn't work," he said.
"The problem for the British government was that we became so enmeshed in American strategy that we had no option but to go along with it, even when it was palpably wrong."
A Downing Street spokesman said details of discussions between the British and American leaders would not be revealed.
He added: "The prime minister and the president have got a very close and good working relationship."