If this was boxing, the referee would stop it

After the poisonous emails, the YouTube fiasco, a discredited Budget, humiliation abroad and the Gurkha defeat, Mr Brown puts the rump of his proposals for MPs' expenses to the Commons this afternoon. It is difficult at this point to see how one man can take much more punishment and - if defeated in the divisions later - it is also impossible to see how this can be allowed to go on for another year.

The choices for Labour are invidious.

They can stick with Mr Brown and go through the European and council elections in a few weeks and then have the disclosure in the summer of all expenses receipts for the past few years, just watching things get ever worse. Death by a thousand headlines. There will be no recovery in business or domestic confidence and abject slaughter is the most likely outcome when the election does come round.

They could "deputise" Mr Brown - ie, send a deputation to tell him the game is up - and put in someone like Jack Straw or Alan Johnson - more able as communicators and certainly more consensual - to hold the Tory majority back. The difficulty is whether the electorate would tolerate another change of leader. There is no need to call an election, but without an immediate poll the likelihood is that Labour would be further punished in May or June next year for perceived political cynicism.

Or they could give up the ghost and call an election. This is not without its attractions as Tory plans do not seem fully formed - are half-baked in fact - and they would get in with the very worst of the recession still to come (we're not quite at the bottom). But leaving someone else to clean up the mess won't be forgotten either. Whatever the millionaire haters and envy politicians say, the mood has shifted and people are no longer listening to all that class war stuff. Instead, they'll grab hold of something they think will see them back to job security, and for that reason the Tories are likely to be in for at least two terms. The voters know austerity is coming and, actually, may be rather more ready and accepting of it than even the Tories realise.

And so why has it come to this? Because of political misjudgment, both tactical on particular issues and strategic when assessing the pathology of the public mindset. The economy is in trouble partly because of Mr Brown's lax regulation but that is not why Labour is in trouble. The really serious, toxic stuff is to do with the Prime Minister's misreading of the issues mentioned in the first sentence, most spectacularly the inept handling of the Gurkha settlement regulations. The wider error has been to think that at a time of recession, the public would somehow shift leftwards and be prepared to accept a high-tax, client state run at a ballooning deficit and with plenty of noise about social justice (Equalities Bill , poor deluded Harriet) but little to show. In fact history demonstrates that in times of crisis the electorate closes to ears to all that and realises that salvation, or just survival, may lie in turning to entrepreneurship and belt tightening. This happened in 1951, when Macmillan defeated the financially busted Attlee, in 1970 when Heath took over after Wilson has been duffed up by repeated sterling crises and in 1979 when Thatcher led the country away from a collective nervous breakdown.

We live in the sort of period that James Callaghan, driving around in his armoured Rover in the days prior to the 1979 election, described as a sea change: a shift so final and determined as to be unstoppable. The shift is not yet totally to the Tories but it is dead set against Mr Brown.