Tim Yeo has indicated that he will pull out of the Tory leadership contest to allow the centre-left of the party agree on a challenger to stop the right-winger David Davis from lifting the crown.
In an interview to be broadcast by GMTV tomorrow Mr Yeo, the former shadow environment secretary who quit the front bench to run for the leadership, said that the centre-left of the party should choose their preferred challenger to Mr Davis within the next month, before MPs go on their summer break.
He said: "Each of us needs to make an honest appraisal of our prospects." Mr Yeo added that some of the eight possible contenders would have to drop out, and he was prepared to make the sacrifice. He said: "I hope we can use the month before the summer recess to find someone to group around."
His decision to withdraw from the field will raise hopes that Kenneth Clarke and David Cameron can form a dual ticket to fight against Mr Davis, who is the favourite to win.
Mr Clarke is expected to use a live television appearance on the Jonathan Dimbleby Programme today to throw his hat into the ring. Mr Cameron, 38, joined the race on Thursday but many regard him as too young and inexperienced to beat Gordon Brown, who is expected to lead Labour into the next election.
Mr Clarke, a former chancellor, is one of the few Tory politicians whom Mr Brown respects, but he would find it difficult to win over his own party, which remains largely eurosceptic, without Mr Cameron.
The other potential candidates who have indicated they could run include Sir Malcolm Rifkind, the former foreign secretary, Liam Fox, the shadow Foreign Secretary, Alan Duncan, and David Willets.
Boris Johnson, editor of The Spectator and Tory MP for Henley, gave his backing to Mr Cameron yesterday on ITV. He said: "He is a very strong candidate. I think I will support him."