Liberal Democrats in Scotland denied yesterday that their policy on local income tax was affected by reported "wobbles" on the issue at Westminster.

Vince Cable, their Treasury spokesman, had been reported as being keen to dump the policy, or at least to use the Scottish experience as a pilot for something he believed was unlikely to work.

But the three candidates for the vacant LibDem leadership north of the Border all leapt at the opportunity yesterday to stress their federal autonomy, insisting that even if their party did abandon the policy at Westminster it would have no bearing at Holyrood.

LibDems at Westminster moved swiftly yesterday to insist that all Mr Cable was proposing was a phased approach, with reform of the council tax as a precursor to an eventual introduction of LIT, and Scotland seen as a welcome test bed.

But the doubts compounded the bad reaction to LIT in the recent consultation exercise, forcing the party's leadership contenders to state their case.

Mike Rumbles, who is campaigning as a grassroots champion, said: "Quite frankly, whatever the English Liberal Democrats want to do is up to them. What is clear is that policy here is entirely up to the Scottish Liberal Democrats.

"Vince Cable is doing a great job but he is not speaking for here, and if I become leader our policy will certainly not be changing."

Ross Finnie, seen as the main challenger to front-runner Tavish Scott, said: "I remain firmly committed to progressive taxation.

"I accept that people have raised some questions about local income tax but I am absolutely clear that taxation should be as far as possible based on the ability to pay."

Mr Scott insisted: "The Liberal Democrats are the only party suggesting Local Income Tax - the SNP support a Scottish National Tax, the Tories are apparently for reform and this past weekend senior Scottish Labour figures are backing reform.

"It would be wise that rather than bicker over this we all work together to reform our local tax system and get the best deal for Scottish families.

"We need urgent action to reduce the heavy burden of tax. That should be our priority."

The contest between the three contenders has been characterised so far by an assumption that Mr Scott, with most of the leading parliamentarians behind him, is the front-runner.

But if there is a party where support from the hierarchy is not a guarantee of success it is the LibDems, where the grassroots relish a self-perception as the awkward squad.

Mr Scott admitted as much this week when he said he would be fighting all the way to August 24 and the final vote.

Mr Finnie is also furiously networking across the country, trying to persuade councillors in particular that he is the candidate to take the LibDems forward.

Mr Rumbles, who won a quarter of the vote in the contest three years ago against Nicol Stephen, plans to go further this time and claims the contest is "wide open".

The Aberdeenshire MSP has made personal telephone contact with the homes of half the party's membership, while his campaign team members have got through to all the others.

"That is quite an achievement," said Mr Rumbles, who said the fact that he was the only candidate to put his home telephone number on his leaflets was striking a chord with ordinary members.