Tony Blair has again rejected calls for a formal parliamentary debate on Iraq, but insisted he was happy to discuss the issue "at any point in time".
The prime minister also made clear that despite suggestions Washington was reconsidering its position in the country, "there will be no change" in the UK's plans.
Withdrawal would only happen when the Iraqi security forces were "confident they can handle security", he said, adding: "To do anything else would be a complete betrayal of the Iraqi people and the sacrifices our people have made over the past few years."
Speaking during prime minister's questions in the Commons, Mr Blair sought to remind people of the "utter barbarity" of Saddam Hussein's regime - an issue he also brought up when asked about trade union rights under the new Iraqi government.
David Anderson, Labour MP for Blaydon, warned the new regime had passed an "anti-democratic" law allowing it to take control of trade union funds, and called for the UK government to pressure for change.
Mr Blair said he had raised the issue, but stressed that the very existence of a trade union movement showed the "absolute transformation" that had occurred in their situation and was a "very great antidote to all those who say nothing has improved since Saddam".
A debate has been raging about the impact made by and the future of British troops in Iraq ever since general Richard Dannatt, the head of the army, suggested their presence was making the violence worse and calling for a withdrawal "sometime soon".
Two polls yesterday showed a majority of the public wanted troops to pull out by the end of the year, but Downing Street blamed the media for only showing the horrors of Iraq and not enough of what progress was being made.
Yesterday, the top US commander in Iraq, general George Casey, suggested Iraqi forces would be "completely capable of taking over responsibility for their own security" within 12 to 18 months, although he said that "maybe" more US troops would be needed.
Mr Blair himself suggested last week that British troops could be out within 18 months, but kept to his mantra that they must stay "until the job is done". However, pressure is growing among MPs to have a proper debate about the UK's strategy.
Earlier this week, Liberal Democrat leader Menzies Campbell said ministers "owed" it to parliament and the British public to have a formal debate on Iraq, and today Conservative MP John Baron called on Mr Blair to commit to such a move.
"Everyone except this House seems to be discussing the possible options in Iraq. Will the prime minister come to the House and lead a full and proper debate in the government's time on Iraq?" he asked.
Leader of the Commons Jack Straw last week said he could not promise a debate but said he would be "astonished" if the issue did not come up in the five days set aside to discuss the Queen's speech next month, the subjects of which the Conservatives can choose.
Today, Mr Blair referred Mr Baron to Mr Straw's comments but said he was "happy to debate Iraq at any point in time". But he made it "absolutely clear" that there would be no change in strategy.