A right-wing critic of David Cameron is favourite to be elected today as the "shop steward" for Conservative backbenchers.
Graham Brady, who resigned from Mr Cameron's shadow front bench three years ago to speak in favour of grammar schools, is expected to become chairman of the party's powerful 1922 Committee.
Mr Brady has said he preferred the establishment of a minority Tory government rather than a coalition with the Liberal Democrats. He is standing against Richard Ottaway, MP for Croydon South, regarded as more of a loyalist.
The two candidates last night made their final pitches to MPs in an election overshadowed by an attempt by Mr Cameron to allow his ministers to vote in the election. The Prime Minister retreated on Monday, announcing that only backbenchers will take part after all.
His about-turn is widely seen among Tory MPs as boosting the prospects of victory of Mr Brady, whose supporters claim he is well in the lead over his rival, while Mr Ottaway's camp retort that the race is very close.
One Tory MP said: "The consensus is that Graham will win. It is a battle between the centre-right and centre-left and Graham is closer to the party's centre of gravity."
Another thorn in Mr Cameron's side is standing for the vice-chairmanship of the committee. Charles Walker was the first Tory MP to criticise plans to set a threshold of a 55 per cent vote of MPs – rather than a simple majority – for the Commons to be dissolved.
Also standing for the two vice-chairman posts are John Whittingdale, Nicholas Soames and Peter Bottomley – none of whom could be regarded as leadership loyalists.
Three MPs are standing for the two posts of committee secretary. One is the former minister Christopher Chope, who has protested about the "massive watering down" of Tory manifesto promises in the coalition document.