The Tories were facing further embarrassment over expenses today as a backbencher fights a deselection bid.
The St Albans Conservative Association's 300 members are to decide whether Anne Main should be able to stand as their MP at the forthcoming general election.
This evening's meeting follows allegations that Ms Main's daughter lived rent-free at a flat paid for by the taxpayer.
The row is another headache for David Cameron, with shadow Commons Leader Alan Duncan battling to hang on to his job after complaining that MPs were being forced to "live on rations".
The Tories have a majority of just 1,361 over Labour in the St Albans constituency, with the Liberal Democrats close behind in third place.
It is understood that Ms Main, who won the seat from Labour in 2005, will address the meeting before an association spokesman does likewise. Members will then be asked to vote on whether to de-select her.
If the bid to remove her is successful, the 52-year-old backbencher will remain a Conservative MP but will not stand as the party's candidate at the next general election - though she could stand as an independent.
A Conservative Party spokesman said simply that the issue was a "matter for the local association".
The claims against Ms Main are being investigated by parliamentary sleaze watchdog John Lyon. The Conservative Party's scrutiny panel has deferred ruling on Ms Main's expenses while the probe is ongoing.
A number of MPs have announced their intention to stand down following the expenses scandal, while Labour barred five of its MPs from seeking re-election.
Scores have also been ordered to repay money they claimed, while a new independent body has been established to govern MPs' pay and perks.