Nick Clegg's Lords reform battle

David Cameron was sitting beside Nick Clegg at the start of his statement about proposals for a mostly elected House of Lords. Less than half an hour later, he had shimmered away. An omen? In fairness Mr Cameron had an appointment elsewhere, before the Liaison Committee, the Commons super-committee made up of select committee chairs.

But Mr Clegg must be getting used to going out on constitutional limbs.

As with the ill-fated attempt to change the voting system, the Coalition Agreement allows proposals on Lords reform to be brought forward, without guaranteeing Conservative support for tanking them through.

And if the rather rowdy reception to Mr Clegg's statement demonstrated anything, it was that few MPs feel very bound by the commitments in the manifestos of the three main parties to Lords reform. The likes of Bernard Jenkin and David Winnick shrugged dismissively when reminded of them. Equally telling was the open contempt directed at him by Conservative backbenchers, who clearly feel the balance of power in the Coalition has swung decisively against the Lib Dems.

One of the best observations came from the SDLP's Mark Durkan, who suggested that the whole process was "a penalty shoot-out in which no-one is going to score", which may encapsulate the fears of those who wish to reshape the Lords.

There are those who want an all-elected upper house; there are those who want to reserve some places for appointed crossbench or independent experts; there are those who want the Bishops out; there are those who want to keep them in.

There are fears that an elected Upper House might lead to parliamentary gridlock, with permanent conflict with the Commons. And there are calls for any reform to be sanctified with a referendum - with the unspoken hope that it would meet the same fate as AV.

Mr Clegg is plunging into a briar patch, and may find the thorniest tangles in the Lords, where an impressive array of vastly experienced peers are poised to try and tie him in knots. Perhaps the most wounding moment in today's exchanges came when the views of his predecessor Lord Steel (the artist formerly known as David Steel) were quoted against him.

And the final battle, if he gets that far, could require him to invoke the Parliament Act, the mechanism by which the Commons can over-ride the Lords, to push his changes through. And that could be a battle too far in 2014 - requiring political energy which the government may not have, or may wish to direct elsewhere.

The next event to watch out for will be the naming of the joint committee which will scrutinise the Draft Bill. The expectation is that it will be chaired by a senior peer - with some Lords gossip pointing to the former Labour Leader of the Lords, Lady Jay.

We shall see - but managing the huge conflicting pressures on this Bill will be a Herculean task for whoever is chosen to fill this hottest of hot seats.