IN the pre-election Commons bearpit, Blue Dave morphed momentarily into Vicky Pollard with a no but yeah but no answer as he dodged Ed Miliband's generous invitation for a one-to-one TV leaders' debate.

Over recent weeks, the Prime Minister has been the picture of wriggling reluctance; insisting on the one hand, of course, he wants to engage in the head to heads with other party leaders but on the other putting up any barrier he could find to stop them from happening.

Initially, the chief comrade tried to up-end Flashman on immigration, recalling the Tory leader's infamous "no ifs no buts" promise to get the numbers down to below 100,000; they are in fact, er, nearly 300,000.

As the shiny-haired premier stressed how immigration from outwith the EU had been cut, he acknowledged it had, okay, risen from within the EU. But the reason for that was - Britain's booming economy.

As Red Ed, veins throbbing musically in his forehead, suggested, given the Tory chief had broken his promise on immigration, no one would believe any of his election pledges, this simply gave Blue Dave the excuse to run through a few commitments he had kept.

And as he rolled them off from pensions to health spending, the Conservative berserkers shouted their approval. To Tory roars of more, Dave snipped: "There's lots more; perhaps I should keep going."

But Speaker Bercow jumped up to cut the PM short; much to the annoyance of some Tory backbenchers, who believe their former colleague is nothing more than a parliamentary pipsqueak.

As the noise level grew, the Tory chief had what appeared to be a pre-arranged stunt to embarrass his opponent by asking how many MPs would be putting the chief comrade on their campaign leaflets.

Labour backbenchers, arms crossed, looked stoney-faced while up popped a hundred Tory hands. "Come on, hands up," roared a beaming Cameron.

So, it was all about leadership, declared the Labour chief, to nodding Tory heads. He then challenged Dave to go toe to toe with him in a live TV debate on April 30. "I will be at that debate, will he be?"

The PM shamelessly dodged the question, so Red Ed tried again. But Dave insisted, to the red contingent's utter fury and disbelief, they were in fact having a head to head debate right now.

The live Cameron-Miliband show might arrive on a TV screen near you before May 7 but don't hold your breath.