Image caption Mr Clegg seemed comfortable in his new seat at prime minister's questions

Five years after his first performance at PMQs, David Cameron finally had the chance to face the questions rather than pose them.

But, this was not the jolly post-election political knock-about that some might have expected.

There were several reasons for this.

Most obviously, the shootings in Cumbria subdued the Commons. The raid on the Gaza ship, and more deaths in Afghanistan contributed to a much more sombre mood than had prevailed in the chamber after the Queen's Speech.

It is also important to remember that over a third of these MPs will never have attended prime minister's questions before.

Many will have been unsure how to behave while watching these fascinating, but strange, weekly bouts.

When to cheer? When to jeer? And aren't the rules for the "new" politics supposed to be somehow different from the "old"?

Clearly, PMQs in the age of coalition will take some time to bed down.

'Punch and Judy'

David Cameron seemed to want to present himself as a less overtly political prime minister than Gordon Brown.

When he first become opposition leader, he said he would end "Punch and Judy" politics in the Commons. That didn't last. But, Mr Cameron still likes to present himself as the serious, grown-up leader acting in the "national interest" at all times.

Labour's tactic week-in, week-out will be to try to tease out divisions between the Conservatives and the Liberal Democrats In video: PMQ highlights

Hence, the prime minister's best moment today: "I am going to give accurate answers rather than make them up". There was a huge cheer from the government benches at this point - even from Liberal Democrats like Chris Huhne.

The role of the Lib Dems in these weekly clashes still is not totally clear.

Nick Clegg has become the silent man - the only leader of the three biggest parties who does not get to say anything at all (although he does seem to be offered the chance to tour TV and radio studios on the morning of big parliamentary events).

Today he sat in the Commons looking pretty comfortable.

At one point, he was licking his lips reflectively.

Sure-footed Harman

A few minutes later he prompted the prime minister about a policy detail.

Week in week out, he will be sitting to Mr Cameron's right.

But never cheering or laughing too enthusiastically for the comfort of his own MPs, and never patting Mr Cameron's back too vigorously when he sits down.

Other Liberal Democrats also seem a little unsure how to react to "their" prime minister.

There will, of course, now be obsessive discussion every week about where everyone is sitting.

Are the Lib Dem ministers huddled together or interspersed with their Tory partners?

As the weeks go by, we can also expect much more comment on the body language of the likes of Vince Cable, Chris Huhne, Danny Alexander etc, as Mr Cameron defends the government's actions.

What of Labour?

Harriet Harman put in another sure-footed Commons performance.

Though she was not as effective or funny as on the day of the Queen's Speech - when many were asking why she was not running for the Labour leadership.

But one thing is clear - particularly from her questions about tax breaks for married couples.

Labour's tactic week-in, week-out will be to try to tease out divisions between the Conservatives and the Liberal Democrats.

The opposition's aim at PMQs will be to expose these cracks in the coalition.

Their hope will be to make the silent Nick Clegg squirm.