FIRST, there can be nothing more pointless than declaring a winner from the daft format of seven leaders lined up like a daytime TV quiz show.

Such an overcrowded studio for tonight's leaders' debate was a surefire recipe for frustration - as promising snippets of debate were quickly cut short to give someone else their precious allotted seconds with the mic.

Only when Nick Clegg and Nigel Farage went head-to-head on whether immigration can be controlled with Britain in the EU - with genuine passion on both sides – did debate truly flow.

My sympathy was with Julie Etchingham, the presenter, who struggled like a teacher trying to break up a fight in the school playground - and decide who started it.

However, I think it was clear who will be most disappointed by last night’s debate – and that leader will be David Cameron.

The prime minister performed competently enough – certainly better than in last week’s bruising bout with Jeremy Paxman, if strangely passionless – but things did not go as he hoped.

The Tory plan was for him to bounce back by displaying calm competence, while pointing to the noisy, squabbling - mainly left-wing - parties, threatening chaos and disarray if let near power.

But it didn’t happen, partly because the debate was so tightly controlled, but also because Mr Cameron so often seemed isolated, rather than “in control” as the Tory spinners briefed.

On the economy, when it’s simply a debate between the big three Westminster parties, Ed Miliband is out on a limb, arguing for more spending and slower deficit reduction than the others.

But, last night, the Greens, Plaid and the SNP – the last two with fresh, impressive female leaders – were alongside him, warning of the human cost of harsh austerity.

Indeed, they attacked Labour for planning to cut too much, which suddenly left Mr Miliband as almost the man on the fabled, sought-after centre-ground.

Meanwhile, Nigel Farage was happy to make UKIP the bad boys, slapped down for condemning the treatment of foreign HIV patients – but maybe doing no harm with his target audience.

By the time people vote on May 7, last night’s froth and fury will matter very little, I suspect – but it will have done nothing to calm growing nerves in the Conservative camp.