Boris Johnson has thrown his weight behind David Cameron to succeed Michael Howard as Conservative leader.
Mr Johnson said his own hat was staying in his sock draw
Mr Johnson backed Mr Cameron shortly after the Witney MP said he was "contemplating" entering the race.
Mr Howard has said he is going but not until just before Christmas so the party can change its constitution.
Spectator editor Mr Johnson was sacked from the frontbench by Mr Howard but remains a popular figure among grassroots party members.
He told ITV: "I hope that David Cameron removes his hat from wherever he has got it, and chucks it firmly in the ring."
The Henley MP added: "That hat has got to simultaneously decapitate his competitors and land in the ring. He is a very strong candidate. I think I will support him."
Finding the plot?
Quizzed about his own ambitions Mr Johnson said his headgear was staying in his sock drawer - but he complained that if there was a plot to get Mr Howard to stand down early he was "frankly insulted" he had not been asked to take part.
"Nor would I take part in any such plot," he quickly added.
Mr Cameron, who is 38 years old, has backed Mr Howard's plan to stay on as leader until later in the year and denied he was already starting his bid for the job.
The current leadership system, brought in under William Hague, sees MPs choosing their two favourite candidates, with the party membership across the country then choosing between those two.
This system has been used just once, when Iain Duncan Smith beat Kenneth Clarke to the leadership in the vote of party members.
Mr Howard's preferred option to replace it would have seen the final choice returned to MPs, although party members would have had a vote to sift down candidates.
But Conservative MPs voted for a system under which Tory activists would be consulted, but with MPs making the final decision on who should be leader.
Although Mr Cameron said this was "basically" the same as that proposed by Mr Howard.
David Cameron was a former adviser to Michael Howard.
Some MPs are frustrated by the lengthy leadership timetable and fear it will turn the autumn Conservative conference into a contest.
There are rumours that lists of names being collected to force a confidence vote which would speed up Mr Howard's departure.
Other MPs insist they should respect Mr Howard's timetable.
Other possible candidates in the frame for the leadership include: David Davis, Kenneth Clarke, Liam Fox, Alan Duncan, Tim Yeo and Sir Malcolm Rifkind.