MP Paul Marsden has quit the Labour Party to join the Liberal Democrats, it was announced today.
The Shrewsbury and Atcham MP has been involved in a series of rows with Labour over first, his opposition to the war in Afghanistan and then the Government's anti–terrorist legislation.
Mr Marsden accused fellow Labour MPs of behaving like "thugs" towards him because of his opposition to the Government.
Liberal Democrat leader Charles Kennedy said: "I am very pleased to be able to welcome Paul Marsden to the Liberal Democrats."
Mr Marsden, who entered parliament in May 1997, said: "This has been a tough decision. There's been a lot of agonising over many months.
"Like more and more people in this country I have lost confidence in this Labour Government ... I'm sick and tired of giving the Government the benefit of the doubt."
Mr Marsden, who held his seat with a majority of 3,579 at the last election, said in a statement released by the Liberal Democrats: "Labour's let people down. But there is an effective alternative. Having thought about this over many months, I am convinced that the Liberal Democrats stand for honest and credible policies which can change this country for the better.
"The values which I find most important in politics are tolerance and integrity. I have experienced enough Labour intolerance in recent weeks to last a lifetime.
"I want to belong to a party which encourages debate and practises genuine internal democracy. Tony Blair is behaving in an increasingly arrogant and presidential manner.
"His party believes in threats and intimidation to crush internal dissent."
It is believed to be the first time a sitting Labour MP has defected to the Liberal Democrats, which will bolster the party's claim to be the "effective" opposition to the Government.
Members of the Pro–European Conservative Party, led by John Stephens, a breakaway Tory MEP, have also joined the Lib Dems. The seven–strong group includes Sir Anthony Meyer, the ex–Tory MP who once stood as a "stalking horse" candidate against Margaret Thatcher for the Tory leadership.
The Tories later pointed out that although the move by the Pro–Europe Conservatives had been billed by the Lib Dems as defections, those concerned had in fact left the party to form their own group two–and–a–half years ago.
"They have left their own party to join the Lib Dems," said a Tory source.
Mr Kennedy said of Mr Marsden's defection: "Paul has worked hard since his election in 1997 to represent the best interests of his constituents.
"It is clear that he feels those interests are no longer represented by a Labour Party that is so comprehensively failing to deliver on its promises.
"The Liberal Democrats are the party he now trusts to work in the best interests of the British people.
"After five years in government, Labour is failing the National Health Service. Indeed, the chairman of the Labour Party himself admitted recently that parts of the NHS have got worse since they came to office.
"Secondary schools class sizes are now higher than they have been for years. Police numbers are lower now than in 1997. Our rail system is in a shocking state and getting worse.
"The Liberal Democrats are now the effective opposition to this New Labour Government.
"Together these new supporters from Labour and the Conservatives send a powerful signal. The Government is no longer trusted, the Conservatives are too extreme and the Liberal Democrats are now the party of the future in British politics."
Mr Marsden becomes the 53rd Liberal Democrat MP and the Government now has a working majority of 164.
Danny Moore, the Labour leader of Shrewsbury and Atcham Borough Council, said he was disappointed at Mr Marsden's decision and called it a "betrayal".
He told PA News: "My feelings at the moment are ones of disappointment and regret that Paul couldn't have had the courtesy to talk this issue through with senior members of the constituency party.
"To reflect Paul's own view, having accused myself and other party members of betrayal, there is no other greater act of betrayal than this."
Mr Moore added: "If Paul Marsden has any degree of credibility left within him, he ought to consider standing down completely, fighting a by–election on a Liberal Democrat ticket and not betray the constituents of Shrewsbury and Atcham who voted for him in June this year.
"A lot of people stood by Paul during some difficult times he experienced within the local party. A lot of people spent a lot of time and commitment in returning him as an MP.
"I have more sympathy for those people than I do for Paul Marsden."
A Liberal Democrat spokesman said Mr Marsden had made the decision this morning to join the party, although he had been considering the move for a number of weeks.
He told a number of party officials of his decision at an undisclosed location in central London after driving from his constituency earlier today.
The spokesman added that Mr Marsden had been speaking recently to Liberal Democrat MPs Lembit Opik and Matthew Green, whose constituencies neighbour his.
"I think he spoke to them over several weeks, they were the main conduit. He only made his final decision today."
The spokesman said there was strong evidence of tactical voting in the Shrewsbury and Atcham constituency at the last election, with a large number of Liberal Democrat voters backing Mr Marsden.
"He was regarded as someone who was quite independent of the Labour Party in a lot of ways.
"He has had some difficulties with the Labour Party for some time."
The party's home affairs spokesman, Simon Hughes, said on Sunday that Mr Marsden should instead become an independent.
"That is Simon's view," the spokesman said. "Simon said that when Emma (Baroness) Nicholson joined us. It is very much a minority view."
The spokesman said despite Mr Marsden's opposition to the war, it was not the official party line.
But he added: "We certainly called for restraint and we said no blank cheques, and we are against cluster bombs.
"The difference is that we are a tolerant party and that those issues are argued about openly and honestly."
Although Mr Marsden is the first Labour MP to defect to the Liberal Democrats, the last defection of its kind was Christopher Mayhew, who joined the Liberal Party in 1974.
Mr Marsden's defection now means that the Liberal Democrats, as successors to the Liberal Party, have the highest total of third party seats in the Commons since 1929.Reuse content