Illustration by Nick Hayes

For the first time since 1975, when the British people voted by a two-to-one majority to stay in what was then called the European Community (EC), Brexit – British exit from the European Union – is a possibility. The odds are still against it, but the margin between stayers and would-be quitters is narrowing all the time. Part of the responsibility lies with David Cameron. He is the Ethelred the Unready of the 21st century. He has forgotten that paying Danegeld (the protection money that Viking raiders demanded) only encourages the Dane to come back for more. The Europhobes in the Tory party walk ever taller, partly because Cameron has been afraid to cut them down to size and partly because he is petrified by Ukip.

But Ed Miliband and Nick Clegg are also to blame. Miliband must know that social democracy in one nation is unfeasible. The voracious, masterless, resurgent capitalism of our time and the gross inequalities and social fragmentation that are its stigmata cannot be held at bay by a single, mediumsized European nation state, however well intentioned its government may be. Outside a European Union moving slowly but surely towards more political and economic integration, a Miliband government would be as tightly constrained by the forces of global capitalism as were the Blair and Brown governments of yesteryear. Yet “one nation” Labour has signally failed to offer a coherent and principled challenge to the Europhobic tide surging through the Conservative Party. As for Clegg and the Liberal Democrats, their contribution to the European debate has been little more than a series of bleats from the sidelines.

As a result, the debate over Britain’s relationship with the rest of the EU has been a prolonged exercise in missing the point. Europhobes see Brexit as a Get Out of Jail Free card, liberating our island race from bossy Brussels bureaucrats, but leaving everything else unchanged. They cannot bring themselves to see that the complex, humdrum activities of the Brussels Euro-village have become part of the woof and warp of British politics, British economic life and British jurisprudence; that secession from the EU would have a drastic impact on virtually every aspect of British politics and government.

Yet even their opponents rarely ask the crucial questions: how would Britain’s political and moral economies fare after Brexit? What niche would she occupy in the global economy? What would happen to the increasingly fraught relationships between the several nations of the United Kingdom?

One or two near-certainties stand out. A post-Brexit Britain would be a cross between a greater Norway and a greater Guernsey. British firms trading with EU countries would still have to abide by EU standards, as Norwegian firms do now, but the British government would have no more influence on them than the Norwegian government has today. Britain would be excluded from the endless round of wheeling and dealing that shapes EU policies on the vast range of topics over which EU institutions (notably including the European Parliament) share power with national governments. Britain could survive outside the EU; she might even prosper. But her prosperity would depend, even more than it does now, on the competitiveness of her financial sector. Frankfurt would strain every nerve to capture business from London; and in a post-Brexit world it would be well placed to do so. Fending off that challenge would inevitably become a top priority for British governments. Rebalancing the economy in favour of manufacturing, an objective shared by all three main political parties, would take second place.

The logic of self-exclusion from the EU points, in fact, towards a market society, governed by a market state, presiding over a glorified tax haven and financial services hub. In such a society, inequality would rise yet more. Public trust – above all trust in politicians and political institutions – would decline still further from its already dangerously low level. There would be more poverty and more of the humiliations it brings with it. Collective action to redress the ills associated with poverty would be even less feasible. The already battered public realm of equity, citizenship and service would yield still more ground to the invasive market realm. The welfare state would continue to erode. The hateful language of “shirkers” v “strivers” and “scroungers” v “hard-working families that play by the rules” would sound ever more loudly. Britain would be a harder, more selfish and, above all, nastier society.

A second near certainty, however, is that where Europhiles speak to the head, Europhobes speak to the heart. They appeal to a myth of glorious, insular self-sufficiency that swamps memories of the long centuries of British involvement in the cultural, religious, ideological, political and military history of the European mainland. It is an odd myth, to say the least. To read the tabloid press or listen to Europhobic speeches in the House of Commons, you would think that the Dutchman William of Orange had never been king of England; that George I had not been a German princeling; that Waterloo had not been a German victory as well as a British one; that the echt Englishman George Orwell had not fought in the Spanish civil war on the same side as Spanish anarchists and Trotskyites and against Spanish Fascists; and that hundreds of thousands of British men and women had not been killed in world wars triggered by ethnic conflicts in eastern and central Europe.

But in the battle between head and heart, facts count for little. The myth of insular selfsufficiency has tough, deep roots, watered by a long line of poets. Shakespeare’s John of Gaunt famously compares the “blessed” realm of England to a “precious stone set in the silver sea”; his Bastard in King John resonantly declares: “Nought shall make us rue,/ If England to itself do rest but true.” In one of the best-known passages of his Areopagitica, John Milton exclaimed that God was revealing himself “as his manner is, first to his Englishmen”. Blake’s “Jerusalem” is another example of the genre. So is Benson’s “Land of Hope and Glory”. Yet another is Rupert Brooke’s celebrated lines, written at the start of the First World War, that if he were to die in battle there would be “some corner of a foreign field/That is for ever England”.

There is a paradox in all this which the paladins of Brexit resolutely ignore. The heart to which they speak is English, not British. North of the border and west of Offa’s Dyke, Shakespeare’s John of Gaunt and Philip the Bastard, Milton’s vision of England as a providential nation, Blake’s “Jerusalem”, Benson’s “Land of Hope and Glory” and Brooke’s corner of a foreign field cut little ice. For what it’s worth, polling evidence suggests that a significant majority of Scots are against Brexit, while the Welsh are evenly divided. But polls matter less than the deeper forces of memory and myth – the “mystic chords of memory”, as Abraham Lincoln called them – that shape a nation’s self-understanding and existential choices.

In Scotland, these forces increasingly recall the long, proud history of the independent Scottish nation that defeated the English at Bannockburn, nurtured the Declaration of Arbroath which insisted that Scotland’s king could rule only with the consent of the Scottish people, allied itself with France against England, embraced an austere Calvinism closer to Geneva than to Canterbury, and eventually negotiated a voluntary union with England which protected the idiosyncrasies of the Scottish Kirk and legal system. The subsequent Scottish Enlightenment gave birth to the economics of Adam Smith and the philosophy of David Hume, both thinkers of European as well as Scottish significance. Geographically, Scotland is farther away from the European mainland than England (except, of course, in relation to Scandinavia); yet emotionally, intellectually and culturally, she is closer. Already there are signs that, in response to the English myth of insular self-sufficiency, the Scots are crafting a national myth of Scotland as a proud, centuries-old European nation whose contribution to European civilisation has been out of all proportion to her size. The more clamant English Europhobia becomes, the more powerfully such a myth is likely to resonate north of the border.

The Welsh story is more complicated. Unlike Scotland, Wales was conquered. The bizarre tradition that makes the heir to the English crown Prince of Wales is a badge of Welsh subjection. (It remains to be seen what will happen if a woman becomes the heir.) Under the Tudors, Welsh by origin, Wales in effect was incorporated into England. For many English commentators in subsequent centuries, the Welsh mountains were England’s Highlands. A notorious Encyclopaedia Britannica entry – “for Wales, see England” – epitomised the patronising indifference with which the English viewed their turbulent western neighbours.

Yet, against all the odds, the Welsh language survived and prospered as a vehicle for high culture and not just as a peasant patois. Despite a steady decline in the number of Welsh speakers, it still does. More to the point, the political culture of Wales – a culture that nurtured two of the greatest leaders of the labour movement in 20th-century British history, Aneurin Bevan and Arthur Horner – is radically different from England’s. Even more than Scotland’s, it is saturated with an egalitarian (if sometimes inexplicit) democratic socialism, the legacy of the days when coal was king and when Welsh workers fought for justice and industrial democracy against exceptionally tightfisted mine owners.

More important than any of this, the Welsh and Scots are comfortable with multiple identities and multilevel governance in a sense untrue of the English. Whatever the Encyclopaedia Britannica might have said in days gone by, the Welsh have never thought of themselves as English. Still less have the Scots. For both, there is nothing strange or shocking in the notion that you can be both Welsh or Scottish and British. And if you can be Welsh and British you can also be Welsh, British and European. The same applies to governance. The devolution statutes created autonomous centres of power in Edinburgh and Cardiff, reminiscent of Barcelona, the capital of Catalonia, or of Munich, the capital of Bavaria. In Wales and Scotland, public policy has diverged from England’s and increasingly does so. The long-term results are unknowable, but there is not much doubt that there is more divergence to come.

The United Kingdom has morphed almost unconsciously into a strange, lop-sided, unacknowledged quasi-federation, in which centrifugal forces outweigh centripetal ones. The centralised British state that joined the European Community in 1973 no longer exists. That will still be true even if a majority opts for the status quo in the 2014 Scottish referendum on independence: the status quo is more like a squashy blob of mud than a rock of existential certainty.

There can be no worthwhile debate on Britain’s role in and membership of the EU until these simple truths are acknowledged. But though Scots and Welsh people rejoice in them, English reactions vary from blissful ignorance to petulant irritation. The implications are alarming. Given that England is by far the biggest of the different nations that make up the United Kingdom, a UK-wide, in/out referendum on continued British membership of the EU might well yield a majority for secession even if the Scots and Welsh voted to stay in. Naturally, everything would depend on the political conjuncture at the time. Referendum results usually reflect public attitudes to the government of the day. A referendum called by a popular government would be one thing. A vote called by an unpopular government would be another. Yet such niceties are beside the point. What matters is that the European question, which has loomed so large in British politics for a quarter of a century, is inextricably entangled with Scottish, Welsh, perhaps Northern Irish and even English questions – and all these questions affect each other in complex and confusing ways.

The English question is the most intractable. There is more to it than Shakespeare’s John of Gaunt and Milton’s Areopagitica. In England, though not in the other nations of the United Kingdom, the terms “British” and “English” have been almost interchangeable. When Kipling asked “What do they know of England who only England know?” he had Britain in mind. In his magnificent polemic The Lion and the Unicorn, first published in 1941, George Orwell called for a “very English revolution”, but it is clear from the context that by that, he meant “British”. When foreign, imperial and defence policies have been in question, however, terminological roles have been reversed. The empire on which the sun never set was always a British empire; its later incarnation was the British Commonwealth. It was Britannia who ruled the waves and the British Grenadiers whose feats surpassed those of Alexander and Hercules.

Scots contributed mightily to Britain’s imperial expansion. And the Duke of Wellington, arguably the greatest British general of all time, and the conqueror of much of India, was an Irishman, born in Dublin. For the English, however, the British empire was an English empire – just as for Russians the vast, multi-ethnic and multilingual Soviet empire was Russian. The parallel with Russia shouldn’t be pushed too far, but it throws much-needed light on the curious interaction between the European question and the English question. The non-English nations of the United Kingdom have responded to the loss of empire with equanimity. They have sloughed off their imperial skins and rediscovered their much older national ones. And, like other small European nations, they have seen EU membership as an opportunity, not as a threat.

The English story could hardly be more different. For England as for Russia, the loss of empire was traumatic; and far from softening the blow, entry into the European Community rubbed it in. The contrast with France and Germany, the two core states of the EC and later the EU, is particularly instructive. For them, European integration spelled hope: escape from the demons of three centuries of blood-soaked rivalry. For England, integration has spelled demoralisation verging on despair – relegation from great-power status, a petty future in place of a great past. Brexit’s champions present it as a return to greatness. In truth, it would confirm pettiness.

Yet if Brexit comes about because English votes in favour of leaving overwhelm Welsh and Scottish votes against, the probability is that the United Kingdom would break up. Wales and Scotland would stay in the European Union. England would be on her own. Conceivably, just conceivably, isolation would force her to come to terms with reality. It would be a painful process, but it would be better than endless self-deception. Best of all would be a coherent and passionate socialdemocratic and social-liberal challenge to Europhobia. We haven’t seen one yet, but there is still time. Just.

David Marquand’s most recent book is “The End of the West: the Once and Future Europe” (Princeton University Press, £13.95)