Humans are pattern-seeking animals, consciously and subconsciously imposing designs and theories on to past events. We do this in both our private lives and when looking at history. That tendency is as old as the study of history itself. This is what leads the rulers of empires, including those of the modern United States (the empire that will not speak its name), to look to Rome to spot the portents of their own decline and fall.

Many historians will tell you that there are no laws of history and no great cycles that govern human events. History often appears more random than rhythmic. But if not patterns or cycles, there are certainly coincidences and some are so marked that they are hard not to notice. Currently, the odds on one of the most striking coincidences in British history being repeated stand at 60-40, at least according to the secretary of state for international trade and president of the board of trade, the Rt Hon Dr Liam Fox MP.

The coincidence in question is that the 19th year of both the past two centuries has arrived to find the British Isles convulsed and divided. There have been other troubled years, of course, but if you’re looking for patterns in the wandering clouds of the past then you might be forgiven for concluding that for some reason we have a problem with 19th years.

1819 was a year of hunger, mass unemployment, political repression and murderous, state-sanctioned violence. The pivotal event was the Peterloo massacre in Manchester, a cavalry charge on an unarmed crowd of protesters in which at least 15 people were killed, “starv’d and stabb’d in the untill’d field”, as Shelley put it in his poem, England in 1819.

1919 didn’t get a poem, hasn’t made the English literature GCSE syllabus and consequently is much less well remembered. But if you’re looking for an annus horribilis, this is it. Rapid demobilisation, an economy struggling to adjust to peacetime conditions, combined with industrial unrest, the Spanish flu and the conspicuous absence of a “land fit for heroes” in the aftermath of the most terrible war in history culminated in violence on the streets and a genuine fear in government of an impending Bolshevik uprising.

Soldiers awaiting demobilisation rioted in their camps and in Luton the town hall was burned to the ground by a crowd, in the so-called Peace Riot. Tanks were dispatched to Glasgow as it was feared strikes might morph into a revolution and when the police went on strike in Liverpool two Royal Navy destroyers were sent up the Mersey. In nine British cities, mobs attacked minority communities, West Indians and Africans in Cardiff, Hull, London and elsewhere, Yemeni sailors in South Shields.

Frightening warnings about jammed border crossings have led to talk of stockpiling food and medicine. Photograph: Gareth Fuller/PA

With our historic run of form, talk of large-scale job losses, a sterling crash, the stockpiling of food and medicines and crops rotting in the fields or in the backs of lorries on the M20, combined with dark mutterings from the Brexit camp about betrayal, raises the prospect that next year we might make it three in row; four if you count 1719, the year of the Jacobite rising in Scotland.

The odds on 2019 becoming another of history’s ugly sisters shorten further when we remember that Nigel Farage, the leader of what purports to be a political party, warned last year that if Brexit were not delivered, the result would be “widespread public anger in this country on a scale and in a way we have never seen before” and that he personally would “don khaki, pick up a rifle and head for the front lines”. Political leaders in healthy democracies do not speak like that. This is not normal.

Given all this, and our track record, this is a historical coincidence that looks like it might well take that big step towards looking a lot less like a coincidence and more like a pattern.

There are, of course, those who are confident that disaster will be averted and that 2019 will turn out to be a year little different to any other. A deal to minimise the effects of Brexit is still possible and even if we have the hardest of no-deal, cliff-edge Brexits, things will have to go very wrong for 2019 to be anything like as bad as 1819 or 1919. And if there is any great law to British history, it is that even in the darkest, most divided moments we display a strange aversion to revolutionary action, never mind revolution.

But even if some elusive formula is discovered around which a deal can be drafted that satisfies the EU, British business, both wings of the Conservative party and the nation at large, the divisions that have been created and amplified by the referendum will remain.

Nowhere is Britain more divided than in parliament, but no longer strictly along party lines. As a result, the two major parties stand in disarray. If a snap general election had been called any time over the past few weeks, the timeliest slogans would have been “Labour, not a threat to Jews”; and “Vote Conservative – there will be adequate food supplies”. And we’ve not yet crossed the chronological Rubicon into a 19th year.

If in six months’ time we do fall off an economic cliff edge, what future historians might well marvel at most is the way in which we came to regard Brexit almost as external, an irresistible, unstoppable force over which we have no control, like a natural disaster or a global economic crash that had swept in from Wall Street. Just as today’s historians are struck by the parties and general joviality that characterised the long hot summer of 1914, future scholars might wonder how we remained so calm as we approached the edge of the cliff, especially as the decisive moment happened to come in a 19th year.

• David Olusoga is a historian and broadcaster