It was a big day for George Osborne and John McDonnell.

The Chancellor and his Labour shadow both had much to prove.

By the end of it one of them would be cheered on by his backbenchers as he threw a copy of Chairman Mao’s ‘Little Red Book’ at the other.

But it was not quite the way around that you might think.

The tension that surrounded Mr Osborne's Autumn Statement and Spending Review was revealed as soon as the Chancellor walked into the Commons chamber.

In the same room just five months ago he was hailed as a hero by Tory MPs as he pledged to spend two per cent of GDP on defence and announced a new national living wage.

But in the weeks since then the government had suffered a humiliating defeat in the House of Lords over Mr Osborne's proposed swinging cuts to tax credits.

MPs were determined to show their support for their man, even if they did look a little nervous at what he was about to say.

Unfortunately that meant hollering the moment they saw him - interrupting a serious question by the former SDLP leader Mark Durkan around victims of the Northern Ireland Troubles.

But Mr Osborne appeared unfazed.

This was a slightly different politician from the man we have seen at similar statements.

His body language was more confident and his voice, which famously breaks during every Budget he makes, held out.

In fact it was the normally booming voice of veteran left-winger Mr McDonnell which appeared to falter.

He started confidently, attacking the Chancellor for failing to meet his pledge to eradicate the deficit within five years.

And he went on to accuse the Tory MP of being keen to suck up to the Chinese.

It was here that things started to go wrong.

In what Labour aides would later insist was definitely a joke Mr McDonnell told Mr Osborne that he had brought in a copy of Chairman Mao's 'Little Red Book'.

He proceeded to try to quote some of it at his opposite number.

But the sound was completely drowned out by delighted backbench Conservatives who could not believe their luck.

"More, more," they jeered.

Mr McDonnell sent the book across to the chancellor who threw it straight back shouting, as if anyone there had managed to miss the point, that the Labour shadow chancellor was actually quoting Mao.

Earlier Mr McDonnell has suffered at the hands of a Tory wag who after the Labour MP said "there's only so long you can blame past governments" replied "No,no,no..."

Which is not to suggest that it was only the Conservatives who got the best lines.

At one point during his statement Mr Osborne said that the improvement in the economy that he had just announced was down to two things.

Yes, a Labour MP shouted, quick as a flash, "smoke and mirrors".