You could say that the left wing tendency is on the rise. Not in the sense of red flag-waving Corbynistas, but in this sense: nine MPs (at the time of writing) have left the Labour Party, three more have left the Conservative Party, and Britain has all but left the European Union. It begs the question: who’s really left? Or, putting it another way: who has done the leaving?

Anna Soubry, one of the three self-styled Tory “amigos” who defected from the Conservative Party this week, was quite insistent that she had not abandoned her long-held values. “I am not leaving the Conservative Party,” she said. “It has left us.” Over the past 150 years, it has become the most successful political force in British history by providing a home to a vast array of factions—from hard right “Blukip” and “European Research Group” supporters at one extreme, traditional “One Nation” and “Brexit Delivery Group” Tories in the middle, and federalist Europhiles at the other. But, over the past few months, there has been a discernible shift. As Ms Soubry observed, “the hard-line anti-EU awkward squad…are now running the Conservative Party from top to toe.”

A similar transformational shift could be said to have shaken the other institutions: the EU and the Labour Party. The European Union is very far from the economic community that the people of the UK voted to join more than 40 years ago. Bigger, more grandiose, it would become a kind of United States of Europe, if its more ardent supporters had their way. Now, it has only the scantiest claim to democratic legitimacy: as the joke goes, if you know who your MEP is, you’re probably the MEP.

Likewise, under Jeremy Corbyn, the Labour Party, the largest political grouping in Europe, has strayed from its reasonable, centre-ground, electable roots. “The Labour Party has long been an uneasy coalition between socialists and social democrats,” noted Vernon Bogdanor, David Cameron’s distinguished former tutor at Oxford and currently professor of government at King’s College London, after the defections of the Labour MPs this week. “But, under the Corbyn leadership, this has taken on new and menacing forms.” If you heard the words of the constituency party chair for Luton South, after the Labour MP Gavin Shuker joined the Independent Group, you will know exactly what Professor Bogdanor means. “It’s apt that Gavin is one of the Seven Dwarves who have resigned today because he’s a political minnow,” he said. “We look forward to him calling a by-election, where he will be annihilated by the official Labour Party candidate and consigned to the dustbin of history where he belongs.”

The breakaway MPs present their actions as a break with the past. Their language is infused with the rhetoric of the new. “This is about the future,” proclaimed Heidi Allen, as she enthused about “creating something better that is bang smack in the centre ground” of British politics. “This is not about going back.” Likewise, the more passionate Brexiters talk of remaking Britain, striking ambitious new partnerships with fast-growing economies around the globe.

But, to a significant degree, the breakaway reflects a wider cultural trend shaped by a longing for a lost, less hurried, less intertwined time. It is not long ago that Thomas Friedman, the New York Times journalist, won prizes for his pronouncement that “the world is flat”. He noted how global supply chains were “flattening” the world, linking people from different countries and giving them all a stake in the success of globalisation. Now, however, people everywhere seem to be rebelling against the hyper-connectivity of a globalisation facilitated by digital technology.

Marketers talk about an “analogue” backlash, as consumers buy books instead of ebooks, and vinyl records and cassettes instead of CDs.

Anthropologists talk about the “Dunbar number”, after the Oxford evolutionary psychologist Robin Dunbar: we may live in a concrete jungle, but we still live in a jungle, our bodies have not evolved appreciably in 100,000 years, and we are at our most comfortable in social groups of no more than 150 people. And health experts urge us to unplug, switch off our smart phones, and limit the amount of time we spend in front of computer screens.

It is clear that this trend is just beginning, and its wider impact will continue to be felt. In the political sphere, other MPs are poised to join the first defectors while other countries may follow Britain by exiting the EU. And beyond these institutions, others are certain to face the same kinds of pressures—or suffer an exodus.

In the corporate world, chief executives are struggling to adjust to the idea that big is not beautiful and go-go growth should not be their primary goal. This week, Sainsbury’s CEO was shocked by the UK competition regulator’s interim report on the supermarket’s planned acquisition of rival ASDA. Last year, on the day he announced the M&A deal, he was caught on camera singing “We’re in the money” to himself. Now, with the stroke of the regulator’s pen, his bold plans to trampoline to the top of the supermarket league table are all but scuppered.

Perhaps, however, it is the United Kingdom itself that faces the biggest threat in this disconnecting age. Vocal support for independence is loud in Scotland and it has become louder in Ireland since the furore over the “Irish backstop” designed to prevent a hard border in the event of a “no deal” Brexit. In the past, these voices have been silenced by devolution—in effect, the handing back of powers once amassed by Westminster. But what happens when that isn’t enough?

The EU bent over backwards to try to keep the UK within its fold. Remember “subsidiarity”? That was the failed principle—written into the Maastricht Treaty—designed to ensure that power was exercised “as close to the citizen as possible”. Also, the UK was given opt-outs from EU legislation and a generous rebate from the EU budget. But none of this prevented Britons from voting to leave. So what will stop the people of the UK from leaving the union?

As soon as Brexit is settled, this will become the most urgent political question for policymakers. No-one wants to be in power when the United Kingdom of Great Britain and Ireland breaks up—after more than 200 years. But that, it seems, is where the trend for disconnection is going. Writing in the March edition of BBC History Magazine, ahead of his BBC Radio 4 programme The Invention of Britain, Misha Glenny concluded: “My best guess is that, all other things being equal, we will probably be talking about Britain as a historical entity not an active one 100 years from now.”

The “left” wing tendency is becoming a surging, powerful force, driven by deep cultural and even anthropological impulses. But there is a danger that it could go too far. Leaving the EU or a political party is one thing, but if people voted to leave the UK, they really would risk voting to be left behind in a world that is marching ahead.

Misha Glenny’s four-part series “The Invention of Britain” begins on BBC Radio 4 on Sunday 24 February.