The position that the Liberal Democrats slowly built up over five successive general elections vanished in a single day.  A month ago yesterday, they collapsed from 57 seats to eight.  They are back almost to where they were the best part of 50 years ago under Jeremy Thorpe.  On May 7, they were a party of government. Today, it’s possible to imagine that they may not survive at all.

Labour is not going to disappear any time soon.  But it has serious problems.  The party of Harriet Harman (London-based, ethnically diverse, pro-immigration, culturally liberal) has little in common with the party of Simon Danczuk (northern, working-class, pro-tougher controls, a long way away from the capital’s human-rights-lawyer-and-left-wing-media classes).  Tony Blair won Labour three successive elections, but lost the party’s white working-class base – or alienated it, at the least.

It’s the big loser from mass migration and UKIP is positioning itself accordingly.  Then there is Labour’s biggest problem of all: Scotland.  It would be surprising if the party did not recover its position somewhat over the next five years.  But it would be amazing if it recovered it altogether.  The electoral revolution north of the border is as dramatic a convulsion as Sinn Fein’s post-war wipeout of the Irish Nationalists – which was the end of them, by the way.

So Labour’s new leader will have not only to reconcile Camberwell and Rochdale, but to bring them together with Glasgow North-East, too.  This will be a tall order – especially since the advantage which it has held since the 1990s, in terms of vote distribution, has been suddenly and starkly reversed.

All this is obviously excellent news for David Cameron.  And it is a very long way from being the end of it.

Most of the pundits believed that he couldn’t win a majority – including me – and have accordingly been proved wrong.  They must now come to terms with the fact that last month’s result has made him a winner.  But the harsh truth is that the pundits don’t matter very much, if at all.  Most people don’t read or watch them, and those who do don’t take them – sorry, us – all that seriously.

Dan Hodges, Polly Toynbee, Rachel Sylvester, Paul Goodman…those who read the pundits inside the Westminster Village do so largely to play the great game of guess-who’s-been-briefing-whom, and those outside the Village view us, I’m afraid, more as entertainers than educators.  I apologise to members of my trade for being so bleak, but Caliban should recognise his own face in the mirror.

None the less, as Bobby Locke once said, “you drive for show, but putt for dough”.  The pundits drive.  But those who stoop over the ball on the green, their brows furrowed in ferocious concentration, are the pollsters.

It is nearly always correct that a poll, as Lord Ashcroft puts it, is “a snapshot, not a forecast”.  However, the closer polling day approaches, the more this truth begins to break down.  It did so rather noticeably on May 7.  This is why the pollsters are reviewing their methods, and the British Polling Council is holding an enquiry.

Whatever the polling companies got wrong they are capable of putting right.  After all, they did so after 1992, an early demonstration during a General Election of the “shy Tory” syndrome.  No, the significance of what happened a month ago lies elsewhere.

It is to be found, rather, in the way that the coverage of politics works.  During the last election campaign, as in previous ones, the pollsters polled and the cameras rolled and the pundits wrote – in that order.  Polling set the framework for the long election campaign that, with the Fixed Term Parliaments Act in place, arguably began as early as the day after the act was passed.

It dominated front page splashes and inside page coverage.  It helped to set the terms of trade for big-ticket interviews by Andrew Neil and Dermot Murnaghan; to frame whatever Nick Robinson or Tom Bradby or Faisal Islam said in their commentary; to shape what voters woke up to on Today or prepared for bed with on Newsnight.

The overwhelming majority of people, of course, follow neither of those programmes.  But the great big rolling collective thing (or Thing, as Cobbett put it) that is this coverage matters.  It is a kind of feedback loop, in which how the critics behave affect how the actors perform.  It is the Observer Effect of physics in a different context.

The pollsters may have a good EU referendum campaign, or a Scottish election next year.  But even if this is so, I suspect that the terms of trade for the 2020 election will be different.  The Thing will be suspicious of polls in a way that it wasn’t last month.  The Thing has had its fingers burnt.  It will proceed gingerly.

So instead of polls driving coverage, at least to the same degree, there will be…what?  No-one can know.  Perhaps – who can say? – discussion and debate about policy will come to the fore.  The future is mist.

All this can only be first-rate news for the Prime Minister.  During the last Parliament, he had little authority (since the Conservatives had no majority), the Liberal Democrats in coalition, and Labour ahead in the polls for most of the time.

Now, he has a majority.  The Liberal Democrats are swirling down the plughole.  Labour’s leadership contest will preoccupy it for some time.  It’s true that the Conservative majority is very small, that Cameron is vulnerable to revolts in the Commons and obstruction in the Lords, and that huge challenges lie ahead for him: human rights reform, the EU referendum, Scotland.

But, for the moment, there is a gulf not only where the official opposition should be, but confusion where the unofficial opposition often lies – among smaller parties, among the taxpayer-funded nexus of left-leaning interest groups, in the media.  And the polling business, which can help to give that opposition projection and impetus, is flat on its back.

No wonder Cameron is moving quickly – ensuring that government will support the Yes campaign in the EU referendum (at least, that’s the plan), insisting that Ministers will have to tow the line, getting on with the measures in the Queen’s Speech.  Perhaps the biggest problem for Number Ten, as it gazes around it at a devastated opposition, cowed pundits and demoralised pollsters, is one which to which the Conservative Party is prone from time to time: overconfidence.