Leading article: The Speaker's last stand

Anyone who did not think that the country was on the brink of a serious political crisis over the expenses scandal must surely realise that it is now. Whatever happens next, the scenes in the Commons yesterday afternoon proved that the current state of affairs is unsustainable. MPs packed the Chamber, expecting – from a torrent of apparently well-informed speculation – that the Speaker would announce his intention to leave office at the next election. Their belief was that this was the minimum Michael Martin could do to expiate their collective guilt.

Mr Martin, though, had other ideas. He offered what has now become the standard form of effusive apology for those in public life, and he offered it several times over. But he did not give MPs what they wanted. Nor did he offer any acceleration of Sir Christopher Kelly's continuing investigation into expenses. And he resisted all suggestion that his own position might be debated.

The furore that ensued accurately mirrored the ill-tempered and tawdry nature of the whole saga. The proceedings were rowdy and uncivil. The Speaker was subjected to a level of personal attack that was unsavoury in its own right and demeaned the whole House. MPs, whose dubious expenses claims have drawn the fury of voters all over the country, cannot expect the Speaker alone to take the rap.

But Mr Martin is the author of many of his own misfortunes; the attack he launched on Kate Hoey, among others, last week was equally unacceptable. Since then there has been breach after breach of parliamentary protocol, including Nick Clegg's demand that the Speaker should go. David Cameron raised the temperature further yesterday, launching a petition to call for an election. Something – and, in the first instance, it has to be the Speaker – is going to have to give.

Will it stop there? Sir Patrick Cormack's comparison of the mood in the Commons to that of the 1940 Norway debate was incendiary. As a Conservative, he is hardly disinterested. But now, as then, the wrath of the people is the invisible presence in the House. We may be looking not just at a doomed Speaker, but at a doomed Prime Minister and government.