A Liberal Democrat councillor in Liverpool has defected to Labour because of his opposition to the coalition government's latest cuts.
Ian Jobling is believed to be one of the first councillors in the country to switch sides since the May elections.
The Picton ward councillor has written to the city's Lib Dem leader, Warren Bradley, to tell him of his defection.
Mr Bradley said: "There are ways to vent your frustrations in our party and crossing the floor is not one of them."
Mr Jobling, who was first elected in 2003 and is a member of Merseyside Police Authority, said the proposed cuts to the police force had really bothered him.
He told the BBC: "On 28 May, when the coalition was only two weeks old, communication came through that we would have to have a £4m budget cut to policing.
"That just didn't stack up with the Lib Dem manifesto. Political parties fight elections from what they put on manifestos and people vote for that accordingly.
"The Lib Dems said before the election that cuts too early could undermine the much-needed recovery and cost jobs - but now they are employing wide-sweeping cuts.
"The promises pledged as part of our election fight are not what are happening, especially in terms of policing and I just found my position as a Lib Dem councillor untenable."
In the letter to Mr Bradley, the councillor, who has been a Liberal since 1976, also said he was unhappy with the cuts to council funding and the scrapping of the Building Schools for the Future programme which have all been imposed by the party nationally, as part of the coalition.
Last month, Mr Bradley spoke out against the coalition, saying the Lib Dems risked being wiped out by the national power-sharing arrangement with the Conservatives.
He added: "I have known Ian for about 30 years, but he has made his decision now and he will have to live with that.
"We just have to get on with holding the coalition government to account."
The Labour leader of Liverpool Council, Joe Anderson, said he was pleased to welcome Mr Jobling to the party.