Miliband plays the middle man as Cameron takes the night off

Because the ultimate victor tonight was the Prime Minister who could enjoy a night off, perhaps in front of the telly with Sam, while his opponents competed to demonstrate who was most different to the Conservatives.

And for his victory lap earlier in the day he had chosen Leeds where he answered questions from staff at O2’s offices, ensuring last night’s TV news interspersed clips of a group of politicians talking to each other and David Cameron talking to real voters.

Yes, there was a big round of applause from the audience when Nicola Sturgeon described Mr Cameron’s non-appearance as a “disgrace” but that was the reaction of a group of people who were engaged enough to give up their Thursday night to sit in a studio listening to politicians not the general public.

From the moment Leanne Wood told viewers “austerity is not inevitable” and Natalie Bennett attacked “spiteful austerity” in their opening statements, it was clear fears among Labour supporters that Ed Miliband would become the de facto defender of cuts would prove well founded.

The first question on tackling debt allowed the nationalists and Greens leader Natalie Bennett to paint Mr Miliband as a slightly paler political shade of Mr Cameron.

Mr Miliband could at least be grateful that the Deputy Prime Minister had also been given a chance to pencil in a night off in his diary.

Nick Clegg has positioned the Lib Dems as the reasonable centre ground option for voters concerned by the Conservatives might cut too fast and Labour not fast enough.

But in his absence, Mr Miliband took the opportunity to portray Labour as occupying the sensible middle ground when he has spent much of this election campaign resisting Conservative suggestions he would represent a radical departure on the public finances.

It was a useful ploy that helped blunt the anti-austerity attack, although he wasn’t helped by Ms Sturgeon’s promise to “work constructively” with other parties in Westminster to deliver “progressive change for people across the UK” – almost writing the Conservatives’ next poster about a possible Labour-SNP alliance for them.

“I don’t say there’s no difference between Ed Miliband and David Cameron; I say there is not a big enough difference between Ed Miliband and David Cameron,” she said.

But if Mr Miliband can sustain that claim to the middle-ground beyond tonight’s debate he may reap the rewards in marginal English seats.

It was another miserable night for Green Party leader Natalie Bennett.

Even her jacket appeared to disagree with the BBC’s staging, producing a distracting flashing effect.

And yet again her answers made her sound more like a university academic than someone seeking public office.

Leanne Wood fared little better, spending too much time looking down at her notes although she enjoyed a minor victory when she focused on Mr Miliband’s apparent linking of the decision to keep the Trident nuclear deterrent and the fight against ISIS.

Nigel Farage spent the evening playing the outsider, going so far as to pick an argument with the audience which he accused of being “a remarkable audience even by the left-wing standards of the BBC”.

In his closing statement, Mr Miliband issued a direct challenge to Mr Cameron to go head-to-head with him in a one-on-one debate.

“I believe my ideas, my vision for the country are better for the working families of Britain. If you disagree, then prove it. Debate me and let the people decide,” he said.

Having watched tonight’s spectacle, Mr Cameron is unlikely to think he has much to gain by accepting the offer.