Quentin Davies, MP for Grantham and Stamford, has defected from the Conservative Party to Labour, on the day before Gordon Brown becomes Prime Minister. In his letter of resignation to David Cameron, he wrote:

"Under your leadership the Conservative Party appears to me to have ceased collectively to believe in anything, or to stand for anything...
It has no bedrock. It exists on shifting sands. A sense of mission has been replaced by a PR agenda...
Although you have many positive qualities you have three, superficiality, unreliability and an apparent lack of any clear convictions, which in my view ought to exclude you from the position of national leadership to which you aspire and which it is the presumed purpose of the Conservative Party to achieve."

I do not know anything about Quentin Davies - indeed, I had never heard of him until his defection today, so I won't be commenting on him as a person at all. I also agree with Bel that Conservatives should not set out to rubbish the man's personality, as that helps no-one at all, even though I agree with Iain Dale that Quentin is being a disloyal s***. His defection is undoubtedly a blow to Cameron and the Conservatives, as all defections are. Especially coming as it is at a time when defections should be going the other way - but that doesn't mean that it is necessarily a bad thing in the long term.

What intrigues me more is what will happen now. Theoretically, elected as he was on a Conservative ticket under a Conservative manifesto, he should resign and hold a by-election in his constituency - but he was already declared that he won't:

"I will consider my future as an MP before the next election, but in the meantime, I will continue to represent the constituents of Grantham and Stamford in the way I have done from the Opposition benches, always seeking to put their interests and the national interests before any narrow partisan considerations."

No, you should hold a by-election. The political system in this country means that although votes are cast for individuals, the vast, vast majority of people cast their votes for the party, not the person. There are few MPs who have a personal vote. As such, Quentin should have to fight a by-election before he can be a Labour MP. This should apply to all defections of elected personnel, especially MPs - whichever party they are defecting to and from.

UPDATE: Quentin Davies' Chairman also says that he should resign and fight a by-election. There is also now the obligatory Facebook group: When MPs defect there should be a by-election.

Image from ConservativeHome
Sources: BBC, The Times, The Telegraph, The Guardian