The Prime Minister Tony Blair will give evidence next week to a US task force looking at future policy in Iraq, Downing Street confirmed today.
He will talk via video link on Tuesday to members of the Iraq Study Group, which is led by former US Secretary of State James Baker.
It will come a day after President George Bush holds discussions with the bi-partisan panel amid speculation he will announce a policy change.
The war has been blamed as a key factor in the self-confessed "thumping" Mr Bush's Republicans took in this week's mid-term elections.
Number 10 said Mr Blair would ensure Mr Baker and his colleagues were "fully briefed on UK ideas" when he spoke to them.
British officials had been in touch with the inquiry since it began and the Prime Minister's intervention was a "natural extension of that", a spokeswoman said.
She would not be drawn on reports that he would use the conversation to urge the US to open discussions with Iraq's neighbours Syria and Iran.
The Guardian said Mr Blair would not call for a rapid withdrawal of coalition troops but would call for talks with the two states and would press for a fresh push on Middle East peace.
Opening contacts with Iran and Syria is believed to be one of the options being examined by Mr Baker's group, which is not due to report its final conclusions until later in the year.
Tuesday's US elections - which saw the Democrats take control of Congress - also led to the resignation of Defence Secretary Donald Rumsfeld.
His departure - and replacement by former CIA chief Robert Gates - has intensified speculation a change of policy may be imminent.
PA