by John Underwood

So there we have it. Vince Cable is surprised to discover that the Conservatives are “ruthless, calculating and thoroughly tribal”. That’s a bit like being surprised that the Pope is a Catholic, that fish swim and that this year Christmas Day will fall on the 25 December. The word “naïve” doesn’t come close.

A man who is surprised that the Conservatives are ruthless would probably be surprised that a couple of young, female “constituents” asking sharp questions at a constituency surgery turned out to be a pair of reporters from the Daily Telegraph.

For years, of course, the Liberal Democrats have been the very embodiment of ruthless calculation, by pretending to be different things to different people in different parts of the country – the “only” alternative to Labour in the north of England and the “only” alternative to the Conservatives in the south.

Last week, they reaped a whirlwind of rewards for years of political duplicity. In the north, they lost votes to Labour because they were seen to be part of a Conservative-led government that is cutting public services; and in the staunch Tory heartlands they lost votes to the Conservatives because die-hard Conservative voters rather like the idea of cutting public services.

Labour supporters can be forgiven a few days of schadenfreude as they reflect on the mire the Liberal Democrats find themselves in. But before long they will need to turn their attention to the Conservatives.

As for the Lib Dems, the question is whether they will learn their lesson and wise up to the need to get tough with their coalition partners.

It won’t be enough to posture and strut over Andrew Lansley’s health service changes and to threaten a “veto”. The current proposals have, in effect, already been vetoed by Conservative back benchers like Charles Walker MP, who is currently leading a particularly vociferous campaign to save an urgent care centre in his Broxbourne constituency. There will be changes to the health and social care bill, but it’s no thanks to the likes of Nick Clegg.

Having been stitched up by the Conservatives on the AV referendum, the question is whether the Liberal Democrats will get tough with their coalition partners in other areas.

Reducing the number of MPs from 650 to 600 has largely been reported as a barely disguised ruse for reducing the number of Labour MPs. In fact, it could be more accurately described as a ruse for maximising David Cameron’s chances of achieving what he failed to achieve at the last election – an overall majority. Reducing the number of MPs is as much about getting rid of his Liberal Democrat “partners” as it is about hurting Labour.

If, in the aftermath of the AV referendum, the Liberal Democrats really want to prove to their supporters that haven’t been taken for patsies, they could do worse than consider a serious “go slow” on this part of the coalition agreement.

John Underwood is a former director of communications of the Labour party.