A litmus test for Cameron's leadership?

Iain Dale flags up a letter in today’s Telegraph written by 27 of the 2005 intake of Tory MPs. They’re asking for the sanctions that MPs face to be tightened, and even suggest the introduction of US-style recall mechanisms:

“…we do think that consideration should be given to creating a recall mechanism, similar to that used in some US states, to enable constituents to vote on whether they remove their MP during the course of a Parliament. For example, in California in 2003, a petition was organised calling for the recall of the governor, Gray Davis. Once it was established that a sufficient number of electors had signed the petition, a ballot was held on whether Davis should be recalled. That ballot succeeded, and Arnold Schwarzenegger was elected to replace him… …a mechanism of this sort used in exceptional circumstances would increase MPs’ accountability, address some of the frustration felt by a disenchanted public and help restore trust in our democratic institutions.”