Under a plan to be presented to the UN Security Council next month, the Iraqi Government would assume authority from coalition troops by the end of next year.

Only hours after Donald Rumsfeld was replaced as US Defence Secretary, American, British and Iraqi officials spoke openly about accelerating the handover process.

Baghdad made clear that it would use the Democrat victory in congressional midterm elections to push President Bush for concessions. Confidants of Nouri al-Maliki, the Iraqi Prime Minister, said that they hoped defeat would make Mr Bush more open to ideas that he had previously rejected.

However, Margaret Beckett, the Foreign Secretary, sought to play down the impact of both the Republicans’ mid-term election losses and the dismissal of Mr Rumsfeld. She said that it was unlikely that there would be a “major upheaval” of US policy in Iraq.

In a speech to the Royal United Services Institute think-tank she said: “We will leave when they are confident that they can take the role of security in the country on their own shoulders.

“I ask those who are calling for more precipitate action to consider the consequences of such action: we would be leaving the Iraqi Government without the means to prevent a further escalation in the violence, without the tools to enforce the rule of law and without the authority to prevent their country from turning into a base for terrorism.”

All sides said that Mr Rumsfeld’s departure provided an opportunity to set a clearer timetable for withdrawing all foreign forces.

A new tone was set by President Bush. He said that he was open to ideas that would help the US to achieve its goals of defeating the terrorists and ensuring that Iraq’s democratic Government succeeded.

The plan being drawn up in Baghdad, with Washington’s approval, seeks a one-year extension of the UN mandate for foreign forces in Iraq.

But it also states that by December 2007, security in the country’s 18 provinces, apart from the most violent, be handed over to the Iraqi Army and police. US and British troops would play a support role.

The process has already begun in the South, where British forces have handed over two provinces this summer and hope to complete the transfer of a third by the year end.

British military sources said that the downfall of Mr Rumsfeld had given the coalition a golden opportunity to “rebrand” its strategy in Iraq. Under his era at the Pentagon, one senior British official complained, there was “very little flexibility”.

The two key aims of the strategy, training the Iraqi Army to take over security and helping the Baghdad Government to spread its influence throughout the country, remained unaltered. But it would be possible now to make clear to the whole Middle East that US and British forces intended to leave Iraq and that the countdown had begun.

Until now Washington and London have rejected setting out a timetable for a withdrawal of their forces. But yesterday British military officials suggested that it could be completed in the next year and a half.

Haidar al-Abadi, an Iraqi MP and member of Nouri al- Maliki’s inner circle, said that the Government hoped to raise the issue of a timetable with the US Administration, which rejected it during negotiations in June. Iraqi officials believe that Washington will be more receptive now because the Admin istration is “weaker” and less stubborn.

Mr al-Abadi said that a timetable would help to destroy the popular support of armed groups, who claim that American troops will never leave the country. Insurgent groups have repeatedly called for a date for a US withdrawal as their precondition for stopping attacks.