The Conservatives have won a mild coup against Labour with the defection of a north London councillor.
Bertha Joseph, Brent's first Afro-Caribbean mayor, said she was joining the Conservatives after Labour failed to address crime in her area or increase the representation of black and ethnic minority Londoners in the council.
Conservative party chairman Caroline Spelman welcomed Ms Joseph's defection as proof David Cameron was widening the Tories' appeal.
The announcement follows a night of indifferent election results for Labour in local council by-elections.
Ms Joseph had been a Labour councillor for 20 years and was twice elected mayor for Brent in London.
She said today she had become frustrated with the inaction of the Labour group in Brent, which she said had failed to address a recent spate of murders and shootings in Kensal Green.
Labour had also not addressed the poor representation of black and ethnic minority staff in the highest levels of the council.
Explaining her move to the Conservative party, Ms Joseph said: "I feel that it is the natural thing to do because of David Cameron's views and attitudes towards youth and crime.
"During his leadership he has embraced our multicultural society in a way that I have not seen projected by the Labour party."
Ms Spelman welcomed Ms Joseph as a woman of "total integrity, honesty and courage."
The Conservatives have also been celebrating yesterday's by-election success.
Ms Spelman said the party was "very encouraged" by the results, which offset the 'Brown bounce' projected by nationwide opinion polls.
The Conservative party chairman said: " Labour should be very worried that in a week when Gordon Brown has dominated the news, the Conservatives have made a crucial gain from Labour in the north and achieved a swing in three marginal seats which would mean three strong Conservative gains in a general election."
The Conservatives are currently portraying an upbeat front in the face of persistent rumours of an early general election.
George Osborne said there had been so much speculation of a surprise general election, Gordon Brown had given the Tories weeks to prepare.
Lord Ashcroft has been pouring funds into their 200 target seats and the party has £10 million available to wage a nationwide campaign.
The Conservatives have played down Mr Brown's poll lead, with Mr Osborne pointing out this was virtually non-existent a couple of weeks ago.
He told the Telegraph: "You get a new prime minister who comes in and because this one wears a tie when he meets the president instead of a bomber jacket, and holidays in Weymouth (for four hours) for the first time in his life instead of going to Cape Cod there's inevitably a novelty factor."
The shadow chancellor said Mr Cameron will use next week's Tory party conference to launch a possible election campaign.
Meanwhile, union leaders revealed this afternoon they had been told to prepare for an autumn election.
A union source told the Guardian that staff working for unions affiliated to Labour had been told to "make themselves available" for a campaign.