Backstage: Credits rolled – and the spinners got to work

Even before the leaders had completed their closing statements, the post-match analysis had begun at the back of the hangar-like hall at Manchester's Hilton hotel, where an army of advisers, aides and political big beasts were mingling with the assembled media in the so-called "spin room".

Labour was first out of the box. "Clegg won it on style, Brown on substance," said a No 10 aide. "This has proved that soundbites just don't work in this format. We wanted him to be relaxed before, and he really was out there. On the economy especially."

That aide was merely the warm-up act for the maestro, Lord Mandelson. On the vital question of the economy, "Cameron tanked," he said. "This format reveals the behind-the-veneer character," he said. "Behind Cameron's veneer was just more veneer."

Just feet away, George Osborne had apparently watched a different debate. "Gordon Brown needed a game-changer tonight, and he didn't get it," he concluded. It "appeared Brown was not telling the whole truth" on immigration and police, Mr Osborne added. As for the assertion that Mr Cameron had been weak on the economy, nothing could be further from the truth. "The battle on national insurance was one of the areas David was strongest." And the poll showing Mr Cameron had come second? "I've only just walked in here. I haven't heard it."

The Liberal Democrats were suitably smug. "Especially in comparison to Cameron, Nick Clegg came out very well," said his former leadership rival, Chris Huhne. "He got out the three things I was keen for him to communicate. He showed his personal sincerity, the policy differences with the other parties, and authenticity."

The tension was palpable. Relaxing their man was a premium before the big event. Mr Brown's team took him for a turn around a north Manchester park. He spent a few stolen moments with Sarah. Mr Clegg completed some last-minute run-throughs. He also opted to take a stroll around the grounds of his countryside hotel. David Cameron had a leisurely lunch with his team.

As the programme began, the spinning soon followed. Just minutes into the debate, the first message arrived from CCHQ. "DC only candidate to apologise for the expenses scandal," it read. "Clear indication that David intends to talk directly to the people." Labour was not far behind. "The Conservatives propose an arbitrary quota on immigration that would not give us the flexibility to respond quickly to changing economic circumstance."

Then the first tense moment. Mr Cameron talked of a "black man" he had met in Plymouth, who had questions over immigration. "Did Cameron really talk about meeting a black man?!" said a Liberal Democrat mischief-maker. It "wasn't rehearsed" said Mr Cameron's team. "It happened the other day." The Tory messages then arrived thick and fast. "Good early reaction from dial groups," said a senior figure. Fifty minutes in and a Liberal Democrat aide confirmed Mr Clegg was doing "really well".

Others disagreed. "Is it me or is Clegg looking down the camera and not at the audience? Looks strange," blogged John Prescott. Alastair Campbell also made his views known. "The longer it goes on the more shallow Cameron looks and the more substantial Gordon looks," he said. "It was Cameron's debate to lose – and he is losing it."