A change is coming. The leading politicians I’ve been talking to recently, while breaking Sunday-breakfast bread, keep saying the same thing: the polling doldrums are temporary. Soon, somebody will forge ahead. The wind is about to freshen. They all think it. The Tories are convinced that another few weeks of good economic news and playing up the Ukip threat a bit more will allow them to cut clear at last. Three points, then five, then six.

On the Labour side, they’re more nervous but they think that the vast public-sector cuts announced in the Autumn Statement and George Osborne’s promise of tax cuts for the better off are slowly being digested by millions of voters, who are concluding that they don’t like the sound of that very much. A great tactical mistake: surely the reward must be on its way.

All of this assumes that the country will “make up its mind”, which, in turn, assumes that there is a single country and that it has a mind and that, if there is and it does, Britain hasn’t, this year, made up its mind not to make up its mind. There are seven leaders pencilled in for the television debate that may or may not happen. It’s perfectly likely that neither of the big parties will break free and that the election will result in the collapse of the centre. Why is this?

The broad background can be briefly explained and is well understood. We have to start in the period between 1983 and 1989, during the chancellorship of Nigel Lawson, when the power of the City was vastly expanded, as a new financial global system, replacing that of Bretton Woods, took hold. Privatisation swept the world. Deregulated banks reshaped themselves with protean slickness. The power of national politics receded, nowhere more so than in Britain. After the fall of the Conservatives, New Labour, far from searching for a reverse gear, bolstered the power of financial markets. That government deployed (and boasted of) light-touch regulation, gave new powers to the Bank of England, brought in private consultancies to Whitehall (and watched benignly as former civil servants went to work for the big banks and private corporations) and used PFIs to raise capital for its favoured projects. This allowed an avowedly left-of-centre government to keep the money flowing and the financial markets happy, while rebuilding tattered schools and opening new hospitals.

During this period, the old City of London underwent a large-scale change of culture, becoming increasingly Americanised as the big Wall Street institutions moved in, bought in, broke up and swallowed. Thus the US sub-prime housing market crisis, which would always have contaminated British banks, felt like a domestic disaster when the crash came in 2007-2008.

International capitalism was rescued by huge government bailouts, with the now much-maligned Gordon Brown, alongside his chancellor, Alistair Darling, playing an important role. With millions of US homeowners facing foreclosure, stock markets plummeting and major British institutions such as Northern Rock and RBS teetering on the edge, many felt that a total collapse of our economic system was coming. It didn’t but the hangover, which has been with us now for seven or eight years, has completely dominated politics, both here and around the western world.

In an unsustainable spending splurge, who is more to blame: the borrower or the lender? That has really been the political argument, with the left blaming the short-term and greedy banking culture unleashed by deregulation, a capitalist orgy, while the right blames the high spending by governments that had been, in effect, bribing their electorates with a short-term prosperity unearned by higher productivity. (Nobody, of course, blamed the public for a massive increase in personal indebtedness during this period. Going shopping – and staying shopping – had become a fundamental western human right. Democratic

politicians tamper with it, or criticise it, at their peril.)

In Britain, at least, the right won the argument. Initially, much of the public blamed the banks; some bankers, such as RBS’s Fred Goodwin, became hate figures in the media across the spectrum. Popular culture largely agreed. From Up in the Air (2009) to The Wolf of Wall Street (2013), there was a spate of movies portraying the greed, hollowness and madness of the pre-crash financial system – remember Inside Job (2010) and Too Big to Fail and Margin Call, from the following year? Non-fiction books such as Tetsuya Ishikawa’s How I Caused the Credit Crunch and novels such as Sebastian Faulks’s A Week in December and John Lanchester’s Capital took a similar stance. On the stage, we had many satirical assaults on the financial system, of which Lucy Prebble’s all-singing, all-dancing Enron was perhaps the most energetic and popular.

Some day, there will surely be a thesis about why this avalanche of cultural analysis apparently had so little effect on domestic politics. For, when it came to the fight between the defeated Labour politicians and the newly elected coalition ones, the repeated assertion that the real problem had been profligate overspending under Gordon Brown and Tony Blair seemed to win. As a result of the vast sums required from the public purse to save the banking system and the shrivelling of tax receipts as the recession continued, all governments had to rethink their public spending trajectories. The good times, fuelled by a cosy relationship between politicians and international capital, were over.

Perhaps Brown, Ed Balls and Ed Miliband were so exhausted and demoralised by their experiences between 2007 and 2010 that they simply didn’t have the rhetorical energy to defend themselves effectively against George Osborne and David Cameron in the blame game. Perhaps it was inevitable that politicians would be blamed more: banks, by and large, don’t stand for re-election. And perhaps the public, contemplating its maxed-out credit cards and remembering the good times, had an instinctive sympathy for the masochistic message of austerity.

Margaret Thatcher applauds Nigel Lawson in Brighton on October 1988. Photo: Clive Limpkin/Associated Newspapers/Rex

Whatever the reason, the initial view of a social crisis caused by out-of-control capitalism was replaced by the belief that it was a bloated, out-of-control state that was largely to blame. That has probably been the single most important political fact of the past five years. We know that austerity has caused much suffering, for most people on welfare and for very large numbers of middle-income voters. Yet the bringers of austerity remain relatively popular, with the Tories at around 33 per cent, while the Labour critics of austerity are at roughly the same poll rating: just as popular, no more unpopular. However, words such as “popular” and “unpopular” seem inappropriate. The electorate appears to treat the two big, old parties with some indifference, as if they were exhausted boxers clinging on to one another, not quite ready to fall unconscious but entirely unable to deliver a vigorous final punch. That’s not much of a spectator sport.

Therefore, does the big story ahead of the 2015 general election not go like this? We had two grand political narratives offered to us in postwar Britain and they have both gone pop. The socialist story, which was that the public sector and public servants could be trusted to deliver a fairer and more decent society, could not survive the left’s brief alliance with turbocharged capitalism. Socialist critics of Tony Blair personalise this too much. It was a huge political defeat for social democracy, which began in the Thatcher period and continues today. Meanwhile, the free-market story, which promised a “virtuous cycle” of ever-greater prosperity, shared in by almost all, was also smashed by the events of 2008. The proposition that if you simply taxed people less and regulated business more lightly, you would find a stable, relatively fair and prosperous society growing automatically is one that even leading pro-market thinkers find hard to expound with a straight face.

Thus, the centre is gently collapsing – not simply mealy-mouthed, easy-osy, compromising, milk-and-water centrism or one-nation compassionism but the notion of there being a centre at all, a relatively stable central party system that is able to deliver coherent parliamentary majorities. All around the hollowing centre are multiple populisms, rubbing their hands – a populism that blames foreigners and Europe, a populism that blames the English-dominated state, the populist politics of Protestant Ulster, the left-wing populism of the Greens. These populisms are not the same. Of course not. They are often mutually antagonistic. Yet they each offer a single culprit for all social ills and they seem to be in a position of influence that we haven’t seen before – and that is, to recap, because of the collapse of the two old stories that once dominated Britain’s political imagination.

I have been simplifying. There are many other aspects to the collapse of the centre worth reminding ourselves of, as we head towards polling day. All of those stories about the failure of public bodies to behave properly or to protect the public – the terrible sex scandal stories, from Oxfordshire and Rotherham; the historic failures inside the BBC; the failures inside the NHS, leaving people to die in corridors – undermine the entire social-democratic narrative. If public servants can’t be trusted to look after sexually vulnerable teenage girls, why should we trust them to do anything else?

On the other side of the spectrum, the stories about tax evasion rip into the Panglossian suggestion that the attitudes that led to the crash have vanished, or even that the financial system possesses an uneasy conscience. Day after day, stories that are,

in essence, about the failure of authority, public and private, and the necessity of general mistrust are fed to us. We are left to join up the dots. We do so.

It’s possible to imagine ways in which the two big parties could recover some of their authority and attraction. Our biggest economic problem isn’t actually the deficit, serious though that is. It’s our lack of inventiveness and productivity. Unless we can find the ideas and the things to sell around the rest of the world, we are sunk. So one can imagine a pro-business social democracy that throws its energies into science, engineering and higher education.

Labour now lives in a world dominated by big business: to achieve greater fairness, it could simply use its power as a government purchaser to make private companies pay the living wage and their taxes and offer more apprenticeships. It could slaughter the vast number of tax loopholes accumulated under different governments. There are the glimmerings of such new thinking visible behind tax-and-spend but they are not nearly clear enough and confident enough yet to show through.

The Tories, meanwhile, could have taken their compassionate conservatism seriously and done more to spread the pain. Those black-and-white balls and friendly hedge fund managers almost seem like a series of acts of wanton self-harm. Tim Montgomerie’s “Good Right” project is the most interesting response and Michael Gove’s call for the Tories to be crusaders for the powerless shows that some Conservatives understand their plight. Perhaps if Cameron took all this more seriously, he might begin to make more ground.

Overall, however, we are now so close to the election that any big change of message from either Labour or the Tories seems unlikely. Neither party, certainly, can try to distract the voters with global stories to help itself out. Today, the British look abroad and see, mostly, the results of our own past failures (Iraqi, Syria, Libya) and our own current weakness (Ukraine, Isis). If there were one part of the state – the watchman state, for instance – that was operating conspicuously more effectively than the rest, then there might have been a left or right gain. But there isn’t. So those two old boxers resort to the politics of fear: Ed Miliband is in Alex Salmond’s pocket, one side says; David Cameron plans to abolish care for the elderly, says the other.

The collapse of authority and self-confidence at the centre of politics has consequences across society. One early example is the lashing anger and lack of civility in public discourse. Most Britons are in employment and average earnings are slowly creeping upwards again; few of us are immediately threatened by violence or disorder. It’s not 1929 and it’s not 1939 but there’s a remarkable amount of fear and fury swilling about.

Moderate, moderately spoken feminists are warned that they will be raped if they don’t shut up. Hard-working public servants are trolled. Some Scottish nationalists take a little time off the moral high ground to taunt my BBC colleague Nick Robinson about his cancer. It’s not just them; the poison is everywhere. People say that it’s always been there – it’s just that Twitter gave it wings. But I wonder to what extent the increase in anger can be explained by the falling away of the traditional left-right ideological argument, by the collapse of the centre? If we don’t have the old grammar for arguing about our future, we are more likely to turn personal and self-righteous.

A second, more important consequence is that we are quite close to losing the state in which most of us grew up. I think it’s highly likely that we will see enough Conservative and Ukip members elected to deliver an in-out referendum on Britain’s membership of the EU within two years. The way things are, it’s quite likely that we will vote to leave. If Scotland wanted to stay and England wanted to go, what would that do to the already shaky Union?

It may, anyway, be close to over. I hold my hand up and admit that I was one of those who thought, last summer, that the “Yes” campaign was on course to win. Since then, the surge in SNP membership and support has been remarkable. Labour’s Jim Murphy has the hardest job in politics.

But it could well be too late. There comes a time when the decay of political parties is inevitably followed by the decay of the power structures they inhabit and give life to. Scotland now appears to be so far to the left of England, or rather the English south, that the separate parts of the UK cannot continue together. Yet if the Union is over, the political shape of England will change, too – you can’t stop a landslide at one arbitrary point. Manchester and the north will demand many more powers from a Westminster government, which may, for other reasons, have had to desert the Palace. In England, the party system will rearrange itself. Everything will look and feel very, very different.

It would be wrong to regard such potential changes in a maudlin, pessimistic way. Change can revive as well as undermine. Perhaps we haven’t had enough of it in our political system over the past two centuries. However, the world is a dangerous place just now and this doesn’t seem the best time to replace a relatively unpopular coalition with a weaker government, whether led by the right or the left.

No voter is going to go into the booth and vote for instability. But if we are collectively saying, “None of you is worth supporting,” then “none of you” – radical instability, an unpredictable clatter of change, a weak centre – is what we are voting to get. “None of the above” sounds like a fine, high-minded slogan. It wouldn’t make much of a government.

Andrew Marr’s most recent book is the novel “Head of State” (Fourth Estate)

He appears at the Wapping Project Mayfair, London W1, on Thursday 26 March, in conversation with Erica Wagner, in association with the New Statesman: book tickets here.