SCOTTISH TYCOON SIR TOM HUNTER HAS ENTERED THE constitutional debate by calling for a referendum on independence.

The billionaire philanthropist told the Sunday Herald last night he believed the referendum should be a simple yes or no question rather than being multi-option.

"The matter is far too important for the future of our nation to be decided by a single transferable vote system," he added. "That would be far too complicated for such an important issue.

Hunter's intervention was welcomed by First Minister Alex Salmond, who said: "Opinion is coming down between those who believe in the right of the people to determine Scotland's future - a position carrying 80% support - and those who don't.

However opposition parties and political commentators did not agree on the need for a referendum, or how it should be framed. Jim Drummond of the Scottish Constitutional Convention, was unsure if a single question on independence could work. "Independent of what," he asked. "Independent of the Monarchy? Of Europe? You would need to define what independence meant from the get-go - and it can mean different things to different people.

And Electoral Reform Society Scotland director Amy Rodger said: "If you are going to have a multi-option referendum, particularly with an issue of this significance, it has to be done in a considered way and that means you have to have preferential voting."

Hunter told the Sunday Herald he had chosen to speak after the events of last week, when Scottish Labour leader Wendy Alexander launched her constitutional commission, and First Minister Alex Salmond responded with the Scottish government's national conversation.

Hunter insisted: "This matter has to be debated fully. I have not made up my mind on the issue but I would be very interested in hearing the debate in full. When I was reading about the matter last week I found it very difficult to get my head round the issue. If I am in that situation so is the electorate.

"I am not criticising any individual party, but am calling on the whole political class to get their heads together to have a full public debate on this."

Hunter was adament the referendum should be a simple yes or not vote so that the people can decide the future of Scotland.

"I have never made my views on independence known and I genuinely have still to decide on the mater but I certainly do not want independence to happen by default. I certainly don't want a referendum that can be manipulated by any political tactics.'' Despite that caveat, First Minister Alex Salmond said: "I welcome Sir Tom's intervention. The National Conversation is galvanising debate, with a positive and enthusiastic response across Scotland.

"The SNP's first choice is to have a for or against referendum on independence, and that 2010 is the right sort of timescale. But we are perfectly willing to include the option of enhanced devolution on a ballot paper - if the London-based parties can agree on such a specific scheme.

"Labour will struggle to explain their opposition to allowing the people to choose their own future - even one which includes their preferred option! In 1992, it was Gordon Brown himself who demanded that all organisations support a persistent, determined, and concerted' campaign to force the then Tory government to accept a multi-option referendum on Scotland's future."

A spokesman for the Scottish Conservartives said: "Referendums are appropriate for significant constitutional change and when a parliamentary majority exisits to push through that change. There is no majority in the Parliament or throughout the country for independence. There is no need for a referendum."

A spokesman for the Liberal Democrats said: "If the SNP believe their own spin they can call a referendum on independence immediately if they are confident enough. It is the job of the supporters of independence to make the case for a referendum."

Last night a spokesman for Labour leader Wendy Alexander failed to respond to requests for comment.

Jim Drummond also welcomed Hunter's intervention and said he would encourage him to join the Convention and debate the issues. "In terms of getting the parties together, that's exactly what we are proposing - to be be non-partisan, and completely inclusive. Only when you get the parties together will we actually get some proposals."

Writer and historian Neal Ascherson said holding a referendum with a single question might settle the question, but pointed out that views were likely to change in the future.

"What Scottish people think about independence now is probably not at all what they will think in 10 or 15 years time," he said. "I think that has to be taken into account - you have this idea of let's clear this up once and have it tomorrow', but most people say we don't want independence'.

"You then face the fact that actually support for independence is likely to increase, but you have managed to slam a door on the future and tried to lock it.

"All that means is there are a lot of people 10 years from now who will have a certain amount of trouble unlocking that door, so why bother?"

Ascherson argued there would also be problems with holding a multiple question referendum, as it was unlikely to produce a clear majority for any solution. He said there should be more debate around individual issues, such as whether the Scottish Parliament should have fiscal autonomy or control over migration.

"I am all for people talking about having national conversations, but what about the people of Scotland - nobody is really asking them," he said. "It is not a question of asking them are you in favour of what we are proposing, it is a question of asking what is it you want?."

Political commentator Pat Kane said he did not agree with Hunter's view that a simple yes or no vote on independence was the best way forward.

"I don't think that fits the state of the debate at the moment," he said. "I think it is a wee bit of let's try and nail the option of independence, so that it leaves the national conversation.

"We need to have a full discussion and full referendum on all the constitutional options. A three option referendum on no change, enhanced devolution and independence is the best way to go."