Britain's Liberal Democrat leader Sir Menzies Campbell has announced his resignation with immediate effect.
Sir Menzies Campbell addresses the Scottish Liberal Democrats annual conference on October 6th.Photo: Chris James/PA Wire
A statement from Sir Menzies was expected after his party slumped to 11 per cent support in the polls, prompting widespread discontent among MPs.
The decision by British prime minister Gordon Brown to call off a snap election was believed to have been a determining factor in the party's MPs deciding to ditch Sir Menzies.
Earlier today, the party's deputy leader, Vince Cable, admitted the leader's future was "under discussion".
Announcing the decision in a brief statement, Liberal Democrat president Simon Hughes said that throughout his political life, Sir Menzies had taken all of his own decisions and that this was one of them.
"Sir Menzies Campbell has submitted his resignation as the leader of the Liberal Democrats with immediate effect," Mr Hughes said in a brief statement to reporters.
Simon Hughes, Liberal Democrats president
"For the last two years Menzies has given huge purpose and stability to our party. He has led the professionalisation of the party and he has led the very successful preparations for the general election, whenever it comes," Mr Hughes said.
In his resignation letter, Mr Campbell said: "It has become clear following the prime minister's decision not to hold an election, questions about leadership are getting in the way of further progress by the party.
"Accordingly, I now submit my resignation as leader with immediate effect."
The party's deputy leader Vince Cable joined Mr Hughes for the announcement in London. Mr Cable takes over as acting leader of the Liberal Democrats with immediate effect until a new leader is elected.
Mr Hughes said the timetable for this process will be announced tomorrow.
Campbell had been criticised for his lacklustre performance in parliament, and party colleagues feared he would have been an ineffective leader if prime minister Gordon Brown had called a snap election.
He was considered a "safe pair of hands" who could stabilise the party after his predecessor Charles Kennedy stepped down, admitting he had an alcohol problem.
Under Mr Kennedy, the party achieved its best ever result in the May 2005 general election, winning 22 percent of the vote - but less than 10 per cent of the seats in parliament under Britain's first-past-the-post electoral system.
The party's support in opinion polls has halved since the 2005 general election to just 11 per cent, trailing behind the ruling Labour Party and the main opposition Conservatives.
Additional reporting: Reuters