Grown-up Tories are biting their lips and hoping it will work

Mr Cameron replied: "John Bercow doesn't count." The incident shows how precarious is the position of the 157th Commons Speaker.

So much is against him, not least his own party. But not only is he a Tory loathed by other Tories, he is an arch-reformer in a House that, if you scratch the surface, has little desire to be reformed.

Some of those who voted for him did so as a practical joke, to tease Mr Cameron. Others clutched at a young man who tries to symbolise change in the hope that his election would appease voters repulsed by MPs' dishonest expenses claims, not all of them really prepared for the reality.

Another group was driven by competing negatives - for whom anger at the whips' attempts to install Margaret Beckett finally outweighed their fear Mr Bercow was ill-suited to unify the Commons.

The last Speaker who began his first day in the chair with half the House seething was the doomed Michael Martin - not an example Bercow would want to follow.

As the Standard reported yesterday, a lynch mob of Tory MPs is willing to sack him after the general election less than a year away if he gives them an excuse. Tomorrow's Prime Minister's Questions, an event where Mr Martin was forever making gaffes, will be a massive test of the new chairman's tact and skill.

Mr Bercow is a complex individual who is unpredictable by nature. However, he has some advantages, not least a young family that will make the Speaker's Court ring to the sound of toys and childish laughter for the first time in its history.

The other is a clearly set out manifesto for reform, although it may have to be tempered in the light of the qualified nature of his mandate.

Grown-up Tories are biting their lips for now, hoping they can make it work. If the Speaker gives more power to backbenchers and summons more Cabinet ministers to the Commons to explain themselves when things go wrong, they will be quietly pleased. On the other hand, if he is seen to let ministers off the hook he will never be allowed the benefit of the doubt.

Mr Bercow's first key meeting at Speaker's House today was with Gordon Brown, who is eager to hug the new figurehead of change. Backbenchers will be watching to see Mr Bercow does not hug him back too closely.