Lord Ashcroft has told him he shouldn’t have done it in 2010. Lynton Crosby has told him not to do it in 2015. It’s no surprise that David Cameron is trying to wriggle out of televised leader debates during the General Election – even though he has said he is willing to take part “in principle”.

Time perhaps to dust off one of Margaret Thatcher’s favourite barbs “He’s frit.”

Neil Kinnock tried it in 1992 to try to goad John Major into a TV debate. Major was having none of it and so it was that Cameron came to history in 2010 when as Tory leader he agreed to take part in debates even though he had enjoyed a poll 20% over Labour Prime Minister Gordon Brown. Some 22 million watched these first British TV debates between Cameron, Brown and Lib Dem leader Nick Clegg.

Victory in the Clacton by election in the Clacton by election in October which gave UKIP a Westminster MP to go with its widespread gains in the local and European elections in May opened the door to Nigel Farage getting in on the act.

And shortly after the Clacton result Cameron said he was ready “in principle” to debate with Farage. But there are signs that he may be “frit”.

Miliband, Clegg and Farage who have made it clear they are keen for the debates to go ahead. And Greens leader Natalie Bennett has complained bitterly that plans published by the broadcasters exclude her.

She found an unsuspected ally in Cameron. He appeared to champion her cause telling ITV News: “I’m in favour. but you’ve got to make sure you come up with a proposal everyone agrees to.” He added that he was not sure how the debates could include “one party with one MP in Parliament [Ukip] but not another”. His backing for Bennett was clearly prompted not by some born-again environmentalism but by the hope that a Green surge would hurt Labour and the Lib Dems

The fact is that there have been no substantive negotiations between the parties this has prompted suspicion that Cameron is out to scupper the whole project.

That would make Lord Ashcroft happy. He reckons the debates may well have cost Cameron an overall majority and forced him into the coalition with Clegg. Ashcroft was Tory Deputy Chairman who had been in charge of the party’s marginal seats campaign and its internal polling in 2010. In a forthright verdict on the Tory campaign he said the debates had allowed the Liberal Democrats to portray themselves as the party of “real change”.

Ashcroft views are echoed by current campaign chief Lynton Crosby, according to an Observer report in the summer. It quoted “Downing Street sources” saying the Australian had made it clear couldn’t see “any advantage in Cameron taking part in the debates.”

The Observer reported Crosby hopes to avoid the debates by complicating negotiations between the parties and the broadcasters over the number, style and timings of the debates.

Despite Crosby’s view a Downing Street spokesman told the Observer “The TV debates will happen. Negotiations start in the autumn.”

But, of course, the negotiations haven’t happened even though the broadcasters have come up with plans for three television debates – one of them involving Cameron, Miliband, Clegg and Farage.

Which is why former Tony Blair aide John McTernan is reported to have come up with the idea that in order to break the deadlock Cameron should get the empty chair treatment.

Would that break the rules on impartiality laid down by the broadcaster regulator Ofcom. The Times says No. “The regulator made clear that it wasn’t forbidding broadcasters from holding a debate without one of the main party leaders if they declined to show up.

“The rules say broadcaster must give “due weight” to the major parties during an election campaign but in the context of a TV debate, the rules don’t mean a party leader had to be present to represent those views.”

The only question is who should start the ball rolling. Do Labour, Lib Dem, UKIP and Green negotiators get together and approach the broadcasters or should the broadcasters take the lead? The 22 million people who watched in 2010 might be asked what they think