A Liberal Democrat peer warned his colleagues today that the party could "go down the drain" at the next election if Sir Menzies Campbell remains leader.

The explicit warning, from Lord Taverne, came as Sir Menzies' own deputy, Vince Cable, conceded that his position was "under discussion" - although he denied it was under threat.

Lord Taverne, the former Labour minister and SDP campaigner Dick Taverne, told BBC Radio 4's World at One that he may not be representative of the party.

But he added: “The mood is very much a mood wanting change. They want a change in leadership. There’s absolutely no doubt the overwhelming number of peers want a change.

“My general impression is quite clear – if there’s not a change in leadership, the party goes down the drain.”

He added: “Some senior members of the party should go to Sir Menzies and say, you have given great service in the past but it’s time to step down.”

Sir Menzies – criticised both as too old and too old-fashioned – endured a torrid week at the party conference in Brighton last month but the 66-year-old Scot appeared to have faced down his critics with a fiery address to delegates.

But Gordon Brown's decision not to call an early election – and indeed to wait until 2009 to lay out his "vision" for the country – has reopened the leadership question. Latest polls have put Lib Dem support as low as 11 per cent - less than half the 23 per cent of the vote they won at the last election – as the party has been squeezed by a Tory revival.

One of the party’s senior councillors, Chris Clarke, joined calls for a change in leadership, saying that Sir Menzies should “read the runes, go with dignity, go with the respect you have” and return to the foreign affairs portfolio.

Mr Cable, the Lib Dem deputy leader and Treasury spokesman, sprang rather unconvincingly to Sir Menzies's defence, saying that said that he did not believe any of the party’s 62 MPs would want him to step down.

“It’s certainly under discussion, I don’t think it’s under threat,” Mr Cable said of the party leader's position.

Mr Cable added: “You are getting a bit of evidence of panic under fire. The whole political environment at the moment is extremely febrile and volatile.

“In this kind of extremely turbulent, volatile environment it’s absolutely foolish to rush into decisions with major long-term implications.”

He went on: “Ming clearly will reflect on what’s happening. I think it’s very likely he will wish to continue. He made a commitment when he took on the leadership he would be with us until we had an election.

“The test of leadership is how you perform in adversity and it clearly is a difficult period for us. This is, I suspect, not going to last.”

Mr Cable's admission that Sir Menzies’ future is “under discussion” will do little to calm nerves among MPs, some of whom are said to favour a younger, more dynamic, leader such as Nick Clegg, the party's home affairs spokesman, or the environment spokesman Chris Huhne.

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