The Conservative MP Quentin Davies has defected to the Labour Party today, taking a sideswipe at the leadership of David Cameron, on the eve of Gordon Brown becoming Prime Minister.

In an open letter to the Tory leader, Mr Davies, the MP for Grantham and Stamford, said that the Conservative Party’s values have been overtaken by a public relations operation.

The news is a boost to Mr Brown who has pledged to create a Government of “all talents”, but has so far failed to tempt any Liberal Democrats to take a job in his new administration.

Gordon Brown issued a statement saying that he was "delighted" that Mr Davies was joining Labour.

Mr Davies, who was until today the chairman of the backbench Conservative Group for Europe, criticised the “superficiality” of Mr Cameron and his “lack of any clear convictions”.

“Under your leadership the Conservative Party appears to me to have ceased collectively to believe in anything, or to stand for anything," he wrote in an open letter to Mr Cameron.

“It has no bedrock. It exists on shifting sands. A sense of mission has been replaced by a PR agenda.”

In his first interview after his defection, Mr Davies returned to the attack, telling Sky News that he found the Conservative party's policies were not properly thought through, or were designed mainly for image-making purposes and not in the interests of the country.

"I first had problems a year ago because of, well, two-facedness, I must say, over the European Peoples' Party," said Mr Davies, a Europhile who has disapproved of Mr Cameron's flirtation with Euroscepticism.

"I decided not to leave the party at that time but every week or so it seemed that there was some nasty shock or nasty surprise."

He listed the Tory party's backing for an inquiry into the Iraq war, and its support for abolishing targets in the health services, as further evidence of policies he thought were party political.

Sources in the Conservative Party questioned his motives for crossing the floor: “It is probably more about his desire to be on a front page. When he visited Northern Ireland he told someone who worked for him that it might be good if he got shot because it would get him in the paper - so frankly, Labour can have him.”

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