THE important pre-General Election TV debates could feature Ukip's leader Nigel Farage and the Greens' Natalie Bennett, David Cameron has suggested, but there would be no place for First Minister Alex Salmond in any new format.

The Prime Minister is concerned that the three-by-three TV debates ahead of the 2010 election dominated the campaign too much and so he would like to see any successor debates strung out.

The Conservative leader expressed interest in a mix of formats, the so-called "5-3-2", where one debate would involve five party leaders - Tory, Labour, Liberal Democrat, Ukip and Greens - one would involve Cameron, Clegg and Miliband, while the third would be a straight head-to-head between the PM and the Leader of the Opposition.

But this would mean Mr Salmond - who is still challenging Mr Cameron for a head-to-head before the independence referendum - and his Plaid Cymru and Democratic Unionist counterparts, whose parties have more Commons representation than Ukip or the Greens, would be left out.

The PM said: "I have suggested, perhaps, we should have one debate with all of the parties and so everyone can have their say and, perhaps, we need a debate where the two people who could be Prime Minister debate directly with each other.

"You can have a debate where you have all of the parties. I don't think we could have a party like Ukip, without an MP, if you don't have a party like the Greens, who have an MP."

He added: "There are still issues that have to be ironed out but I helped make the debates happen last time; I am pro-TV debates. I am sure, if our teams sit down, they can come up with the right formula."

But Mr Farage, who recently took on Mr Clegg in two televised debates on Europe, accused Mr Cameron of planning to dodge a showdown with him. And the SNP accused the Prime Minister of being "feart" and "continuing to run from a debate on Scotland's future".