Lib Dem Conference: The Sketch: A party that would love to settle down as Labour's better half

THE LIBERAL Democrats have often been caricatured as the Party of Minor Irritations - comically preoccupied with dog dirt, irregular paving slabs and other such scourges of modern society.

On the face of it, yesterday's debate on Mobile Telephone Masts seemed to meet this stereotype perfectly, the motion setting out to curb the rampant erections of the telecommunications companies. As delegates indignantly protested against the arbitrary microwaving of British schoolchildren, the occasional chirrup of a mobile phone added a soothing, almost sylvan accompaniment to their deliberations.

But this is a party with major irritations, too - and the foremost of these for the Liberal Democrats this year is the exact nature of their relationship with the Labour Party. Was that pre-election fling a good idea after all? And why haven't they called since? Did they really care or were they just using them?

The mood is one of fretful, almost erotic obsession, in which the party finds itself divided between the emotional need to punish the philanderer and the desire to offer him one last chance, in the yearning hope that he will say: "I've been such a beast - it'll be different from now, I promise."

Vengefulness is winning at the moment, it has to be said. The first cheers of the conference - or at least the first to reach my ears - greeted Malcolm Bruce as he sniped at the Prime Minister's Tuscan holiday. Speakers who want to hear the clatter of applause know they have only to take a smack at the current Government to get it - whether it's over the lack of libertarian thrust to the proposed Freedom Of Information Bill or the general timidity about higher rates of taxation. It's a bit like getting your girlfriends round to say how they always thought your ex was a bit mean with money, and then weepily confiding in return that he was never that good in bed anyway.

Unfortunately for the Lib Dems Tony Blair is the only boyfriend in town, however haughty and cold his manner. What's more, there's a curious consistency to the complaints about Labour in government - a clear sense that the hostility stems from disappointed hopes rather than a painful discovery that the couple have nothing in common after all.

And disappointed hopes rarely exist without some of the original hope still there - the fantasy that it could still all be different. The Liberal Democrats can't let go of Labour because they want a party to reform - and they appear pretty happy with their own. In short, they want to be New Labour's better half, a conscience at its shoulder. The big question is; what kind of conscience are they going to be? Is it to be that quiet voice of undeniable authority that saves you from your own worst instincts? Or is it the nagging drone that doesn't stop you sinning but certainly stops you taking any pleasure in it?

Charles Kennedy clearly hopes for something like the former - he hopes to play Mr Knightly to the Prime Minister's Emma, sternly reminding him of his obligations to the poor. The activists, to judge from the sheer relish with which they detail Labour's shortcomings, would prefer a more shrewish approach. They define power - the carrot always dangled to lure them towards a rapprochement - solely in terms of their ability to make Labour do things it does not like. The pain of the other partner is an essential part of the deal.

Even those in favour of continuing co-operation seem to have recognised this masochistic strain in the love-hate relationship. At a packed fringe meeting to debate links with Labour, Matthew Taylor, a Kennedy ally, told sceptical delegates they shouldn't underestimate how hard this is for others. Simon Hughes had just called for an amicable divorce, keeping it all civilised for the sake of the children. Mr Taylor, on the other hand, was playing the role of a Relate counsellor, one who knows that victims occasionally need to feel like victimisers before they can forgive.