Rivals ready to battle for vacant post

Among them is almost certain be former Foreign Secretary David Miliband.

Rumoured to have considered a challenge to Mr Brown in 2008, he will be viewed as the Blairite candidate and has been installed as the bookies' early favourite to take control of the party.

Second favourite is Morley and Outwood MP Ed Balls, the outgoing Children's Secretary, who would be seen by many as a natural successor to Mr Brown given his close ties to the former PM.

Energy Secretary Ed Miliband, David's brother, is also a 6/1 contender to gain the Labour crown and could be a dark horse for the role owing to his easy-going persona.

The 40-year-old Climate Change Secretary is set to address the post-election conference of the Fabian Society on Saturday, with many key Labour figures expected to attend.

Hull West MP Alan Johnson is also liked by the bookmakers at odds of 7/1 to sucked Mr Brown, with Left-wing backbencher Jon Cruddas reported to be also considering a run at the leadership. Deputy leader Harriet Harman appeared to rule herself out of running on Monday.

n Candidates to become Labour leader should be forced to take part in a televised debate, a backbench MP has claimed. John Mann said it would put the runners and riders "to the test" and show whether they could handle the influential format at a future general election.