Mr Huhne said he was 'fairly well-known' within the party

He told BBC Radio 4's The World at One that a previous holder of the job, Paddy Ashdown, had not been well known before taking over in 1988.

Mr Huhne, an economics spokesman, said the "recognition factor is lower" for any MP before becoming party leader.

Sir Menzies Campbell and Simon Hughes are the other candidates.

Tax pledges

Mr Huhne said his years as a member of the European Parliament before going to Westminster at the last general election meant he was "fairly well-known within the party".

He argued: "If you look at the recognition of any party leader, it's always three times as great as the next most recognised person in any party."

The Eastleigh MP also reiterated his commitment to raising "green" taxes, while pulling the lowest earners out of income tax.

He admitted his pledge to exclude people on the �5.05 an hour minimum wage from paying the tax would leave a shortfall of about �21bn.

About a third of that shortfall could be made up by raising "green" taxes to the same level as they were at their peak in 1999, he said.

Sir Menzies, the Lib Dem acting leader and foreign affairs spokesman, will appear on The World at One on Thursday, followed by party president Mr Hughes on Friday.