OVER the years the live political TV debate has played a major role in determining the outcome of crucial votes.

John F Kennedy's success in front of the cameras helped him defeat Richard Nixon, while the first British leadership debates handed a boost to Liberal Democrat leader Nick Clegg's profile, helping him to get into power.

However, it appears Prime Minister David Cameron is less than thrilled at the prospect of locking horns with Alex Salmond in a TV debate on independence.

Downing Street has all but ruled out the prospect of the two clashing. A senior Whitehall source said Mr Cameron was not going to fall for one of the First Minister's "wheezes".

The source said any debate should be with Alistair Darling, the former Labour Chancellor, who leads the No campaign.

Last October, after the signing of the Edinburgh Agreement that paved the way for the referendum, Mr Salmond said he would relish a head-to-head with Mr Cameron.

He said he would take on the Conservative Party leader "now, next week, next year, any time from now until the autumn of 2014". No 10 was non-committal.

Labour appeared horrified at the prospect. It believes the Tory leader to be a liability to the No campaign.

Since then, the issue of a televisual match has gone cold but last week Mr Darling resurrected the idea, challenging the First Minister to a debate when the Scottish Government publishes its White Paper on independence in November.

However, Mr Salmond said he expected to debate the issues with Mr Cameron.

Asked if the Prime Minister was up for a head-to-head debate with Mr Salmond, Mr Cameron's spokesman said: "Mr Darling is the leader of the campaign to keep Scotland in the UK and is making that case forcefully.

"Mr Darling is setting out the case and it's this case opponents will have to give answers to."

This apparent rejection was confirmed by a senior Whitehall insider who stressed: "The two leaders of the campaigns are, in the public's mind, Salmond and Darling, and it's right that is where the debate should be. It would be unlikely that Mr Cameron will debate with Mr Salmond.

"This is not about SNP wheezes but hard facts and clear heads. It's really up to the First Minister to explain why he is refusing to go head-to-head with the leader of the No campaign in Scotland."

It is expected Mr Salmond and his colleagues will continue to make the case for a Prime Minister and First Minister TV clash as it falls in line with the Yes campaign's general political strategy to portray the anti-independence campaign as Tory-led.

A television head-to-head debate of some sorts will be hard to avoid given that the format is now an expected part of the General Election campaign.