With all of us agitating for a new politics it's remarkable how resilient the old politics is. A different voting system ain't going to change that, so don't grieve (or exult) too loudly when the results come in.

The No But Yes campaign has been an orgy of old politics – especially among the pepsi-boys of the new generation. Lies, smears, slurs, counter-slurs, tantrums, threats, double-dealing, backstabbing and Baroness Warsi being likened to Goebbels. They're hard-wired to behave like this even when it's against their interest.

There was a moment in Prime Minister's Questions yesterday when Cameron caught Ed Miliband a terrific haymaker – but only because Labour hasn't learnt the old lesson from William Hague's leadership. A new politician will instinctively be able to cut himself free of the living corpse of a previous administration. "My predecessor was a giant – but we'll never do it like that again, obviously." That's the short version. Hague couldn't do it to Mrs Thatcher and this one can't do it about Brown or Blair.

And so Cameron was able to belt Miliband's extraordinary interview remark back at him: "I'm not going to defend what happened just because I happened to be in the last government."

The hopelessness of that position needs to be felt rather than analysed. But old politics is inclined to say, "I, however, am an optimist" – not understanding that we hear it as, "I'm not ashamed to say I'm psychotic".

MPs' attachment to existing formulae on either side of the House is astonishing. Yvette Cooper accuses Cameron of his own accusation, "taking the British public for fools". Cameron fires Blair's fusillade at Miliband "bandwagons", and "opportunism" while he demands alternative policy as Blair used to demand of him. Miliband complains Cameron "doesn't answer the question" as Cameron complained of Blair, and with a line much-loved of Iain Duncan Smith (Conservative leader between Hague and Michael Howard), Miliband has taken to saying "We can't believe a word he says". It didn't work then either.

On it goes. Bob Ainsworth claimed – as his shadow claimed – that the military covenant was being destroyed. Cameron went into Libya because he refused "to walk by on the other side" and Miliband calls every administrative variation a "broken promise".

"Same old Tories" is at least as well-worn a line as "Labour always leaves a mess behind that we have to clear up".

Underlying this is the enduring illusion of Westminster: "Next time it will be different." Vote us, the opposition, into government and promises will be kept, waste will disappear, manufacturing will be reborn, communities will order their own affairs (bidding, indeed, for nuclear power stations and airports to be built in their midst). These incumbents are liars and incompetents, which is why the fabric of the country is being destroyed.

If that is the illusion, it's one the electorate doesn't suffer from any more. No, if there was a glimmer of new politics it was the way Cameron managed his Coalition through the first 12 months: good manners, good humour and an ease in admitting he is neither omniscient nor omnipotent. But that, alas, isn't lasting either.

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