Sometimes, when politics screams and tears its hair out, history can rush forward with a comfort blanket to wrap round its shoulders. It’s all right, it says, calm down, we have been here before. Britain has left Europe in a huff; and been drawn back in again. It has turned its back on Europe; and turned it back again almost as often. Today is just one of those times.

The ancient province of Britannia was firmly part of the Roman empire for four centuries before that empire’s disintegration forced it to leave, in 410. Two centuries later, in 664, England voted at the Synod of Whitby to rejoin what was emphatically a European union, that of the Roman Catholic church, albeit with many a squabble under the likes of Henry II and King John. In 1534, Henry VIII spectacularly withdrew from that union, and Reformation England held itself aloof from Europe’s wars of religion throughout the 16th and 17th centuries.

Then in 1704, England changed its mind and the Whigs plunged into the war of the Spanish succession against Louis XIV. The Tories reverted to detachment after Utrecht in 1713 and the Hanoverians left Europe well alone. In 1734 Walpole could boast to Queen Caroline that “50,000 men are slain in Europe this year, and not one an Englishman”. The Pitts would subsidise selected European allies but refused to fight with them, until Britain was drawn into the war against Napoleon. It then triumphed at Trafalgar and Waterloo, and a London square and a station were erected as memorials to the cause of a newly united Europe.

At the Congress of Vienna in 1815 Britain helped found the Concert of Europe, to resolve the continent’s future conflicts peacefully. But it soon lost interest, to concentrate on trade with our old friend “the rest of the world” – or rather, the empire. It re-engaged for the Crimean war but disengaged to leave Bismarck his supremacy. Lord Salisbury declared a European policy to be one of “splendid isolation … drifting lazily downstream, occasionally putting out a boat-hook to avoid collision”.

In the 20th century isolation met its nemesis: Britain was drawn into a great war it should have helped avoid. It then appeased France’s desire for revenge against Germany, and appeased its inevitable outcome, the rise of Hitler. When Baldwin in 1934 promised “freedom from adventures and commitments abroad, and no rearmament”, it was the climax of the age of leave. The outcome was a second world war.

Single market enthusiasm

After that war, a new Europe, or half a Europe, saw Britain fully engaged in Nato. But it declined to join the Common Market in 1957, changed its mind six years later, and finally joined in 1973. Thatcher eulogised the Single European Act in 1986 as “a single market without barriers – visible or invisible – with direct and unhindered access … to 300 million of the world’s wealthiest people.” She was ecstatic.

Only at Maastricht in 1992 did the old hesitancy return, due largely to the EU’s drift to “ever closer union”. It upset the delicate equilibrium between the benefits of union and Britain’s sense of independence. John Major declined to join the eurozone and the EU social chapter. The slope was now downhill to two years ago, in 2016. That year, on my count, Britain left Europe for the ninth time in its history.

The lessons of the past are glaringly obvious. The decision to leave is bound to be reversed – some time, somehow. Article 49 of the Lisbon treaty is clear: that any state can apply to rejoin. Public pressure to rejoin will be greater the “harder” Brexit proves to be. Erecting borders and barriers across the Channel is likely to prove so costly and inconvenient as to fuel the rejoiners’ cause.

I think it more likely that the EU will degenerate into something else. The Concert of Europe broke down, as did the 1925 Locarno treaty, because of diminishing relevance amid the strands of Europe’s ever variable diplomacy. Of these, the most serious would be a descent into war. Nato remains somewhat hesitantly in place. In a time of military threat from Russia or elsewhere, it would be the European Union of necessity, and Britain is a full member of that.

A more likely scenario has Europe itself changing and dividing, as its economic space has to adjust to the changing politics, economies and cultures of its nations. The EU has clearly become too insensitive, too brittle, to survive for ever. All Europe’s great settlements – Westphalia, Utrecht, Vienna, Versailles, Yalta – have lasted no more than two generations.

Growing more fragmented

At present, the “populist” states of eastern Europe may mimic Britain and leave. The eurozone could grow increasingly unstable. The lesser tribes of Europe, oppressed by their local nation state, may default to greater separatism, like yesterday’s Slovaks and Slovenes and today’s Catalans, Corsicans and Scots. There can be no doubt that Europe at present is growing more fragmented, separating into its multifarious identities rather than cohering into a single European one.

History suggests an EU that could evolve into a new Holy Roman Empire: a confederation of states, some big, some small, some little more than cities, like Monaco, San Remo and Lichtenstein. The old Holy Roman Empire was much derided by historians of the age of empires. Yet as its biographer, Peter Wilson, has written, its weakness was in truth its strength. It threatened no one. Its status as an essentially German empire guaranteed its members a local autonomy that was “multi-layered, from household, parish, community, territory, region to empire.”

This empire lived, mostly at peace, for an astonishing 1,000 years, until smashed by Napoleon and Bismarck. It gave Europe among its greatest architects, artists, composers and philosophers. From such an example of graduated union I can see emerging one day a new form of union that Britain would be happy to rejoin.

The “populist” states of eastern Europe might mimic Britain and leave. The eurozone might grow increasingly unstable. Others may default to greater separatism, like today’s Slovaks, Catalans, Corsicans and Scots. History suggests the EU may well evolve into a new Holy Roman Empire, through gradations of disunion into concentric circles of sovereignty. There will be many Europes for Britain to want to join. Europe has often felt the need of Britain, as in 1704, 1815, 1914 and 1939. But Britain too benefited from these engagements.

Like it or not, globalisation means states cannot sensibly barricade themselves off from their neighbours. They must find reconciliation and trade. Geography has always been the tyrant of history. You can take Britain out of the EU as often as you like; you can never take Britain out of Europe.

Simon Jenkins is a Guardian columnist and the author of “A Short History of Europe: from Pericles to Putin”, published this week