What has today's debate changed?

A debate which at times will for many have seemed impenetrably complex today boiled down to a single word - a word which on any other day is never heard in the House of Commons - a word MPs are normally expelled for using.

The word is "liar". To the evident fury of Conservative MPs the Speaker ruled that Jeremy Hunt could be dubbed a "liar" in a debate about whether he had misled the Commons and, thus, broken the ministerial code.

It may now seem as if all the sound and fury has changed nothing. After all, David Cameron has made clear that he's backing his culture secretary; the prime minister's independent adviser on the ministerial code says he sees no reason to investigate; and the Commons has now voted to back that judgement.

Much, though, has changed. Mr Hunt may survive but his long-term future looks far from certain. Tory MPs have been given yet another reason to resent their Liberal Democrat coalition colleagues. They will now look for a chance to retaliate. Doubts have been raised about the point of Sir Alex Allan - an adviser who has chosen neither to investigate Mr Hunt nor to advise Mr Cameron.

The prime minister insists that who is in his cabinet is properly - and must remain - a matter for his judgement alone. Ultimately it is his judgement which was on trial today and his judgement which his deputy Nick Clegg refused to back.