For all of us, the public sphere impinges on the private and personal. It could hardly be otherwise. It’s more obvious with big events – a war or an economic depression – but the stresses threatening our society create parallel if less dramatic effects. Ever since the referendum, I have been filled by a growing sense of foreboding as a series of catastrophes in the public sphere has unfolded. Britain is being recast, but not for the better. How our democracy works, the chance of there ever being a liberal, social democratic government, how we relate to our EU neighbours, the prospects for our economy and even Britain as a home for Enlightenment values, all are now in question. There has been no similar period in my adult life.

The threatening new coinage of public debate – “crush the saboteurs” – casts a shadow over our daily conversations and how we think the future is likely to frame our career, family and life decisions. People who can are applying for EU passports; many of the good and the decent want out. We are entering a 21st-century civil war. No shots will be fired, but the divisions run deep.

Britain is a country of the European Enlightenment, or so I have thought. For decades, we have muddled through without a written constitution. But the impact of a referendum that went against majority opinion in parliament, along with a desperately weak parliamentary opposition, a weaponised rightwing media and lack of mass support for the rule of law, has shown how vulnerable our civilisation is to know-nothing populism and a profoundly dysfunctional democracy.

Enlightenment values – tolerance, respect for the importance of fair debate, checked and balanced government, objectivity and impartiality, recognition of international interdependencies – are being trashed. Matters could get very ugly, very fast. It is not just Europe we are leaving, but an idea of Britain.

Over the last week, the scale of the impending disasters started to crystallise. It is becoming obvious that there is no compromise settlement between Britain and the EU that can satisfy both. There cannot be a win-win deal because the EU must show all its members that staying in confers greater benefits than life outside the club. It is a tragedy, thinks the EU leadership, that Britain wants to sever its links completely, aiming for some privileged trade relationship like that of Canada or Ukraine, which the EU is not sure it wants to negotiate and certainly not before Britain’s bills are settled. Britain is thus certain to go over a cliff; the only question is how great the fall.

This pessimism is not just the view of Jean-Claude Juncker and Brussels “bureaucrats”, as Theresa May characterises them. It is widespread, particularly in Germany. Last week, one of the most distinguished figures in German politics, the president of the Bundestag, Norbert Lammert, told an audience in Oxford that, while every effort had to be made to find a deal, unless May radically changed her position the gulf was too wide. The British did not seem even to understand the need for the European parliament’s assent.

There is not enough apprehension about what this would mean. Already, there is a chill settling on the economy. Firms are deferring investment decisions. The commercial property market is at a standstill. There is the beginning of an exodus from the City of London. The economy, buoyed by the strength of the European and world economies over the last nine months in the period of phoney Brexit, is beginning to falter.

The chill can only increase as the scale of the gulf between Britain and Europe becomes clearer. If Britain does crash out of the EU, possibly with sanctions being imposed by our former partners because we refuse to pay what they consider are our proper financial obligations, there could be a further run on sterling, a collapse in overblown property values, a second banking crisis and a deep recession. Worse, the enmity towards Europe thus provoked will poison British popular attitudes, as we suffer a lost decade or more, as our weak economy struggles to compensate for lost markets in Europe. Any deal is better than no deal.

Despite her public utterances, May, or at least her close circle, knows this. But she must manage irreconcilable clashes of opinion. She talks the language of Ukip on Europe, crucial to killing them off, and also to appease her right. But she can also sound like a pragmatic, one-nation Tory. Her concern with the just-about-managing, readiness to address absurd levels of executive pay, embrace of science and an industrial strategy, plus flexibility over taxation all have appeal to the British centre, cemented by her quiet Anglicanism and no-nonsense walking holidays.

We think we know who she is. Yet her right remains untamed and dominant, obsessed with Ayn Rand individualism, deluded by dreams of a new British empire and keen to create a fantastical, low-tax Britain, as a European Hong Kong. The Ukip virus has been injected into the DNA of the Tory party. But for any brand of one-nation Toryism to have a chance of flourishing, this wing of her party has to be faced down – and a deal struck with Europe, however distant it is from her current stance. Nobody knows, even herself, I suspect, whether she will do so. Which is why the Labour party’s evisceration is so damaging – for the party and the country. Thursday’s local election results portend, outside parts of the north-west and London, a devastating meltdown. Labour is set to shrink to 150 MPs or fewer. Corbyn is not a plausible prime minister, nor his team a plausible cabinet – witness the supremely lazy Diane Abbott, incapable of briefing herself before the launch of a key policy on lifting police numbers. Their vision and policy priorities do not approach the seriousness of our national plight.

Play Video 3:46 Diane Abbott's error-filled LBC interview on police funding – video

We need our principal opposition party to force potential responses into the national conversation – federalising the constitution to avoid the risk of national break-up, rebuilding our relationship with Europe, repurposing our economy and reaffirming a new social contract. These would address the challenges in a way that inspires hope. The shrunken Labour party and its leadership’s preoccupation with yesterday’s failed leftism will be incapable of holding May to account. Or, because of the weakness of its electoral support, it has not the heft to threaten political consequences if she backs off from confronting her party’s right and its media allies.

It is a perfect storm. Corbyn must be persuaded to promise that, in the event of the likely crushing defeat, he will stand down after the election, offering Labour MPs some chance of saving themselves and their party. It is improbable. Maybe Labour will be so broken that a new party, with roots in the best of the British working class and committed to Enlightenment values that unite the best of our political traditions, will have to be started with a clean slate. It’s going to be a long hard road ahead.