"I preferred Old Labour to New Labour - at least they had some bloody principles!"

So said Nancy Seear once, after a debate in the Lords. And if ever her words were to be proved true in spades, it is by the decision to whip the Parliamentary Labour Party to vote against the Bill to allow a referendum on AV.

It is, of course, the right of the Official Opposition to oppose. I expect nothing less. However, to oppose a policy contained in your own manifesto for narrow political calculation is pretty shoddy by anyone's standards. Even more so if it was an offer made to persuade Liberal Democrat supporters to switch sides. The message that it sends out is, "we never actually wanted electoral reform, we just wanted to burnish our progressive credentials".

I freely admit that AV is watered down milk, compared to the rich cream of open list STV, but I accept that the latter isn't on offer. But I did expect that any debate would be on the issues, not on how much damage it might do to the Coalition. All I ask is that the British people have a chance to decide, and I'll accept the result.

I can see the logic. The Liberal Democrats want electoral reform, the Conservatives aren't anywhere near as bothered. It is a key plank of the Coalition Agreement though, and Labour thinking would be that if the Bill fell, the tensions within the Coalition would cause a fracture and a General Election. An unpopular administration would be voted out and Labour could return to power under new management. Best of all, those pesky Liberal Democrats would be shafted, and hopefully be reduced to background noise, i.e. not a significant threat, allowing Labour to remain the dominant voice of the progressives.

However, there are elements of the calculation that they might have forgotten. Yes, the cuts might be unpopular, but the public won't forget who created the budget deficit that quickly. Given that a drop in Liberal Democrat support will see more losses to the Conservatives than it will to Labour, Labour will need to take significant numbers of seats from the Conservatives to regain power. That's important, because unless they do, we're back into coalition territory.

At that point, what do Labour offer, and to whom? They specifically ruled out coalition talks with the SNP last time, a deal with the Democratic Unionists would be tricky, Plaid Cymru would probably stick together with their nationalist partner, leaving... errr... the Liberal Democrats.

Labour can't credibly offer electoral reform, they lack a consistent record on constitutional change full stop, public spending is ruled out, and most routes towards reducing the deficit have been ruled out. Most civil liberties legislation involves rolling back thirteen years of Labour salami-slicing, so not much hope there, either. What, indeed, could Labour offer, given their apparent antipathy to pluralism, full stop?

So, perhaps, Labour need to be rather more intelligent in their dealings with the Coalition. It is always possible to be too clever, after all...