Charles Kennedy is to attack the government's "timid" attitude towards British membership of the single European currency.

We Liberal Democrats have been arguing the case virtually on our own for far too long Charles Kennedy

The Liberal Democrat leader will also claim tensions between Prime Minister Tony Blair and Chancellor Gordon Brown on the euro are as strong as ever, in a speech to at Stirling University on Saturday.

Mr Blair told delegates at his party's annual conference in Blackpool that they should "go for it" if the government's five economic tests were met.

And in an interview with BBC Radio 4's Today programme, he pledged not to "hold back" from calling a referendum on the issue for political reasons.

'Tensions at the top'

He said he believed "passionately" it was the UK's "destiny" to be at the centre of Europe.

But, he added, the country should only sign up to monetary union if it was right for the economy and the Treasury's five tests had been met.

Mr Kennedy claims Mr Blair "sounded bold" on the euro, but Mr Brown's speech at Blackpool "seemed to be running in the opposite direction".

"So the contradictory signals continue," Mr Kennedy will say in a speech at Stirling University on Saturday.

"The tensions right at the top of the government seem as acute as ever.

"This cannot continue. The longer it does the harder it will be to win the referendum as and when it takes place."

'Lack of leadership'

Mr Kennedy will say the government's attitude has been "characterised by a regrettable timidity."

And it is "high time" the UK was part of the single currency.

"We Liberal Democrats have been arguing the case virtually on our own for far too long.

"We need more support from those many other people who support British membership of the euro but do not have the courage to argue for it.

"The approach of the Labour government, thus far, has been characterised by a regrettable timidity and a lack of leadership on this issue."