Horsham MP Francis Maude is in the running to replace Iain Duncan Smith as Conservative Party leader.
Bookmaker Ladbroke's began offering odds of 25/1 on Mr Maude after suspending betting Mr Duncan Smith will go by the end of the year.
The odds on him being forced out reduced from 12/1 to 3/1 in just 24 hours in the wake of the "Betsygate" probe by the commissioner for Parliamentary standards.
Mr Maude, a former shadow chancellor, has given no indication he wants the party leadership.
He announced he was returning to the backbenches after his close ally, Michael Portillo, lost the Tory leadership contest in 2001. He had served as shadow foreign secretary under William Hague in the run-up to that year's General Election hammering by Labour.
But Ladbroke's still make Mr Maude eleventh favourite to take over if Mr Duncan Smith quits or is booted out.
The favourite is David Davis, the shadow deputy prime minister, at 11/4.
Ladbrokes spokesman Warren Lush said: "Punters believe the end is nigh for IDS. Bookmakers are under attack from malevolent forces and stand to pay out over £50,000 if he goes before the end of the year."
Mr Duncan Smith spent party conference week fighting off claims of a plot to undermine his leadership.
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