One sign that something has gone wrong with your life is when you start the day by looking at opinion polls.

As any psephologist could explain, this marks you as part of a statistically insignificant minority with too much time on your hands. Ninety nine per cent of real people will vouch for the fact.

Polls are a fragment of the truth at a given moment, the bits of the jigsaw with no straight edges, the ones that only give a clear picture when it's too late to matter. Political parties therefore spend fortunes on these things. For them, a grain of apparent fact is better than nothing. So they miss the point of opinion surveys entirely.

Polls don't matter because of the behaviour they describe, but because of the behaviour they cause. Politicians (and others) spending fortunes would be one effect. Parties junking principles and policies because a few strangers sound a bit discouraging on a Thursday morning is another. The reaction to polls is more important than the polls themselves.

You can see it happen. Yesterday, the working week ended with the usual YouGov survey. Its headline figures read: Con 32%, Lab 39%, LD 11%, UKIP 10%. So Ed Miliband and Labour are still out in front. A Populus poll at the start of the week said much the same: Con 32%, Lab 38%, LD 12%, UKIP 11%. This pattern has been repeated for a while. Conclusions are being drawn and behaviour is being altered.

Look into the YouGov numbers closely and you would have found variations that say something interesting about Britain's future, such as the fact that 16% of Londoners would still countenance the Liberal Democrats, or that only 1% of Scots - the margin of error calls that generous - will have any truck with UKIP. In Westminster, those details don't matter any more than the politics of Scotland, Wales and Northern Ireland matter.

Instead, there is an emerging consensus. Several factors are involved, but one conclusion is reached. There is a good chance, say the sages, of another hung parliament. There is an excellent chance, therefore, of another round of disreputable horse-trading and another coalition in which campaign promises can be shredded. The three "main" parties are preparing accordingly.

On the face of it, this is ridiculous. According to YouGov's numbers, Labour are 10% ahead of where Gordon Brown was at the end of the 2010 election campaign, a campaign in which David Cameron failed to seal an outright victory. Nick Clegg and his Liberal Democrats are 12% short of their 23% score in that contest. UKIP has carved a slice out of the Tory vote. Mr Cameron's failure to secure boundary changes should mean he has a mountain to climb, that Mr Miliband needs only a 3% advantage.

Despite it all, the talk is of coalitions. Mr Cameron, according to in-house reporting from The Daily Telegraph, has been discussing whether to grant his back-benchers a vote on a new deal with the LibDems. Mr Clegg has meanwhile declared himself open to an arrangement with Labour, a notion supposedly backed by a majority of his members in a party survey. Mr Miliband is meanwhile being urged by Lord Adonis and others to remain "open" to a pact with Mr Clegg's replacement.

Has Mr Cameron given up? He might have his problems, but he has the supreme advantage of facing a Labour leader bereft of policies, charisma and public confidence. Does Mr Miliband meanwhile believe that this is as good as it gets? May 2015 is a long way off. Scotland's referendum is liable to throw everyone's plans into disarray, irrespective - though Westminster has yet to grasp the fact - of the result.

What's clear is that these three parties have precious little faith in their own appeal. They would have the courage of their convictions, it seems, if they could find some convictions. Instead, the dominant parties in the UK's dominant legislature make plans to huddle together in the face of wholesale public apathy. One consequence, truly preposterous, is that the LibDems could again emerge as king-makers.

It is preposterous less because a great many of Mr Clegg's MPs are due to lay down their careers for his sake in 2015 than because of the presumption involved. For how many decades have the LibDems complained about the unfairness of first-past-the-post voting? How often have they argued, rightly, that the electoral system is loaded against them? Yet here they are assuming that it is fair to allow a wildly unpopular minority party to shape a programme for government.

Westminster's tripartite alliance, the Musical Chairs Party, face a none-of-the-above vote, and they know it. Labour's failure to assert itself in the face of the Coalition's cack-handed management of the economy is a judgment less on Mr Miliband than on adversarial politics. Mr Cameron repeats that "the last lot" were to blame for everything. Given the mote of truth, Labour's leader fails to identify the beam in the prime minister's eye.

A pre-planned coalition is no sign of political maturity. That's Mr Clegg's patented, self-serving nonsense. Instead, the plotting and the discreet chats stand as evidence of a system falling apart. There are "senior Labour figures" who simply cannot see why a deal with the LibDems would be disreputable. There is a prime minister more comfortable with Mr Clegg than with his own back-benchers. Among those back-benchers, meanwhile, there is wistful talk of a pact with UKIP to secure the Tory heartland.

None of those involved in these conspiracies pause over a simple detail. The word "coalition" will not be on the ballot papers. Instead of a government elected by a minority, as is the British custom, we are liable to end up, yet again, with a government for whom no-one at all has voted formally. Think on that when the referendum arrives.

In 2010, coalition was presented as the product of exceptional circumstances. It was unheard of in peace-time. It excused all concerned, Mr Clegg above all, in recanting from numerous campaign promises. Now a different picture emerges. Not one of these leaders is averse "in principle" to forming a government over which voters have had no say. In two out of three cases - for Mr Miliband, as usual, has failed to be explicit - ­coalition is their preference.

In 2015, with luck, there will be no national economic emergency to excuse a pact. Clearly, however, a new system of Westminster politics is beginning to emerge. Why not? There can hardly be a voter left who has not noticed that the three leaders are of the same species, that their differences are cosmetic, that their basic assumptions - towards the economy, above all - are the same.

The Liberal Democrats paper themselves over the thin crack between Tories and Labour. That should count as revealing, less because of Clegg's ability adopt any position liable to give his party the appearance of power than because of what it tells us about the other two. If the friend of my enemy is my new friend, what conflict is there?

Not one of the three believes it can form a majority unaided. Is there anything else you need or want to know about Westminster and the carve up known as the United Kingdom?