Shadow foreign secretary Liam Fox has suggested he will join the contest to become the next Conservative leader.
Liam Fox believes he would reach out to younger Conservatives
He told the News of the World newspaper he would formally announce his intention on Tuesday.
"I am the only candidate who is going into this contest with a positive vision of the future," he said.
Ex-chancellor Kenneth Clarke and former foreign secretary Malcolm Rifkind have already said they intend to stand in the contest to replace Michael Howard.
However, several other senior Tories are expected to join them including shadow home secretary David Davis and shadow education secretary David Cameron.
Dr Fox - a former GP - ran the Conservatives' 2005 election campaign, which saw Michael Howard's party cut Labour's majority to 67.
After the general election Mr Howard announced he would stand down once a replacement was found.
Dr Fox said: "I'm 43. I've been a minister and a Conservative Party chairman. I can provide a leadership that is relevant to all sections of the party and can reach out to our younger members and MPs".
"I would not be standing if I did not think I could win."
He continued: "Instead of reaching inside ourselves we need to remind the country we are the natural party of government."
The grandson of miners, he argued that his background meant he could appeal to ordinary voters.
"I am from a family that was a Thatcherite success story so I know what it is like to live under a successful Conservative government."
On Saturday Michael Howard called on Tory activists to give the party's MPs the final say on choosing his successor.
The party leader told its National Convention that whoever succeeds him must be confident they "command the clear support" of MPs.