Liberal Democrat leader Sir Menzies Campbell yesterday declared he was ready for a General Election and insisted his age and experience was an asset.

He was defiant as he closed the party's annual conference in Brighton, which has been dominated by speculation about his future as party leader. Some critics have claimed the party needs a younger and more dynamic leader to compete with Gordon Brown and David Cameron.

But Sir Menzies, aged 66, said he had the experience and judgment Britain needed following the "tragic folly" of the Iraq war.

With speculation that Gordon Brown could call an election as early as next week, Sir Menzies placed the Lib Dems firmly on the left of Britain's political spectrum, attacking "Blue Labour" for being too like the Conservatives.

He said Britain must remain in the European Union but called for a referendum on whether to quit, arguing it was the only way to end the damaging rows over Europe. And he said Liberal Democrats would draw up a green Bill of Rights, giving every citizen access to "clean water, pure air and unpolluted land".

He said: "Let me assure Gordon Brown of this - whenever he calls the election, whether it's next week or next year, we'll be ready.

"Now when it comes to the next General Election, I believe there is some speculation that age will be a factor.

"You bet it will. Because I'll make it one. Because with age comes experience, and with experience comes judgment.

"And when you are deciding whether to send our young men and women to war, it pays to have that experience and it pays to have that judgment.

"So, if military action is proposed against Iran, who should the British people trust to stand up to George Bush?

"Should they trust the Labour and Conservative MPs who voted for the war in Iraq? Or should they trust the Liberal Democrats who stood - steadfast - against the tragic folly of that decision?"

Sir Menzies said Mr Brown, who was Chancellor for 10 years before becoming Prime Minister, must accept blame for the collapse in confidence in Northern Rock.

He said: "There have been people queuing in the streets, panicked by worries about their savings.

"In the short term that panic has been stopped. But the underlying problem of excessive debt and reckless lending has not been addressed."

Criticising David Cameron's attempt to rebrand the Tories as compassionate Conservatives, Sir Menzies said: "They are suffering from an identity crisis... when they meet a hoodie, they don't know whether to hug 'em - or hang 'em."

And Boris Johnson, the flamboyant Tory MP known for his shock of bright blonde hair, was described as "the blondest suicide note in history".