The chairman of the pro-independence Yes campaign has said he would prefer a separate currency in an independent Scotland.

In an interview with BBC Scotland, Dennis Canavan said he could "live" with using sterling but would prefer a new currency to provide a "wider range of economic levers".

His view differs from the Scottish Government, which has set out plans to retain the pound if Scotland votes for independence, in what the First Minister Alex Salmond has described as a "sterling zone" with the rest of the UK.

Yesterday, two SNP veterans criticised the party's currency plans, with former deputy leader Jim Fairlie saying an independent currency is a "prerequisite" of full national sovereignty.

Other independence supporters including the Scottish Green Party and the Scottish Socialist Party have also backed a separate currency.

Former Labour politician and Independent MSP Mr Canavan told the BBC: "I am speaking personally here, my preferred option is for Scotland to have its own currency because I think that would give us more flexibility, more freedom. It would give us a wider range of economic levers.

"If Scotland were to have its own currency then it would have far more freedom to do its own thing and it would have a full range of economic levers to determine its own economic policy."

Economics experts in the Fiscal Commission Working Group, set up by Mr Salmond, have already concluded that keeping sterling as the currency in an independent Scotland was "sensible" and an attractive choice for the rest of the UK.

In an interview with Channel Four News broadcast tonight, the First Minister said an independent Scotland's monetary policy would be run by the Bank of England but tax and spending would be set by Edinburgh.

"The platform that we put forward would be the Bank of England would operate as a central bank for both England and for Scotland," Mr Salmond said.

"Certainly you would have a monetary authority in the same way that Luxembourg as an independent country had a monetary authority when they shared a currency with Belgium for over 80 years. That's a perfect example of how it could operate between Scotland and England.

"The monetary policy would be run by the Bank of England, the taxation and spending would be run in Scotland by the Scottish finance minister.

"If we take last year as an example, we would have had that £4 billion flexibility, which believe me in Scottish terms is a lot of money. We could have done a great deal to revive the economy.

"I believe the essence of economic independence is to control your taxation, control your spending, that's what allows you to revive your economy and develop a fairer, more prosperous society."

In a Channel Five interview, Mr Salmond again challenged Prime Minister David Cameron to a debate on Scottish independence and said he is convinced Scotland will vote Yes next year.

"I'd put not just the house, but I've put my entire career on Scotland becoming an independent country," the First Minister said.

"We'll win this referendum. And the reason we'll win it is because we're the only force in this campaign which is offering a message of hope about the future of Scotland."

Mr Canavan said it was not surprising that there were different political views within the Yes Scotland camp over key issues.

"We don't believe in control freakery in our Yes Scotland campaign," he told the BBC.

"We don't tell people what to think and what to say and we don't shut people up. It is not surprising that there are different views being expressed. We are a democratic movement.

"What unites us is this firm belief that in an independent Scotland, the people of Scotland, through their elected representatives, would be able to shape their own future."

Former Chancellor and leader of the pro-Union Better Together campaign Alistair Darling said: "How on earth can they ask people to vote for independence when they can't even agree amongst themselves the most basic and fundamental things like what currency we would use?

"As their confusion over currency has escalated, their credibility has evaporated."

Scottish Labour's Ken Macintosh said: "The First Minister is trying desperately to assure Scots that everything will continue much as it has before, but the fundamentalists in the nationalist camp give the game away.

"If the Yes campaign can't even agree what they mean by independence, it is difficult to see how they can expect Scots to vote for it."