Mike Rumbles has declared his intention to stand

Transport Minister Nicol Stephen has already declared himself in the contest to replace Jim Wallace.

Mr Rumbles said if he won and became deputy first minister he would not want a specific ministerial post and hoped he would not have to enter a coalition.

He also said the Lib Dems should demand full tax powers for Holyrood and an end to the council tax.

These, he said, would be non-negotiable.

The 48-year-old MSP for West Aberdeenshire and Kincardine will now battle Mr Stephen for the leadership.

The transport minister was the first to declare an interest in replacing Jim Wallace, who has been leader in Scotland for 13 years.

It's going to be a David and Goliath task, but after all, David did win Mike Rumbles Leadership candidate

Mr Wallace, 50, said he planned to stand down officially as leader at the end of June.

Mr Stephen, the Aberdeen South MSP, is said to be favourite to win the election and has the backing of nine MSPs, including fellow Scottish Executive minister Ross Finnie.

Mr Rumbles has claimed the support of three Holyrood colleagues - Donald Gorrie, Andrew Arbuckle and Mike Pringle.

A former Army major, he has been an outspoken backbencher since 1999 and said in the past that he hoped Mr Wallace would not take the party into a third coalition deal with Labour.

However, he paid tribute to Mr Wallace and said the party faced "a new political landscape in Scotland" with the potential to win seats across the country.

'Clear choice'

Mr Rumbles said he would not be standing for the post if he did not think he could win.

"It's going to be a David and Goliath task, but after all, David did win," he said.

"This is all about the members of the Scottish Liberal Democrats, it's not about the 16 votes of the MSPs or even the MPs or anyone else.

"This is about a one person, one vote election."

Nicol Stephen is the current favourite to take over from Jim Wallace

He added: "It's about going back to core values that people in the Scottish Liberal Democrats really recognise and making a clear choice and giving the members that choice.

"I have to tell you that I do feel I can win this election because I took 48 hours after consulting with parliamentary colleagues to test the water throughout Scotland.

"And I'm delighted to say that I've received a lot of support from our members throughout the country."

The timetable for the leadership election has been set by the party's national executive following a meeting in Edinburgh.

Nominations close on Friday, 20 May, and the final day for returning ballot papers will be Thursday, 23 June.

The result will be announced on Friday, 24 June, in an election conducted by one-member-one-vote and the single transferable voting system, said a party spokesman.