With Britain leaving Europe, can London remain a capital of the world?

LONDON — St Pancras International rail station, a wonder of Victorian architecture resurrected for the 21st century, opened 10 years ago as the embodiment of a particular notion: That Britain is part of something bigger than itself and that belonging to a fellowship of nations is as easy and natural as stepping onto a train.

It was both shocking and thrilling, at first, that you could catch a Eurostar from a platform in London, slide under the English Channel, hurtle through the French countryside and less than three hours later pull into the Gare du Nord in Paris. To ride the Eurostar was to marvel that the capitals — London so prosaic and straightforward, Paris so romantic and mysterious, the two with their long history of rivalry and discord — were part of the same larger enterprise.

Eurostar symbolised an era in which London seemed to be inevitably rushing toward Europe, too. At least that was the idea until now, and the beginning of the process known as Brexit. The trains are still running, but the era that created modern London appears to be over.

“We’ve made a horrible statement to the rest of the world, and it’s very sad,” said Mr Martin Eden, a publisher waiting to catch the Eurostar to Paris the other day, to celebrate his 43rd birthday. “We should be moving together,” he said of Europe, “instead of moving apart.”

I met Mr Eden as I wandered around St Pancras at the moment Britain officially filed for divorce from the European Union. It was lunchtime on March 29, Brexit Day, as you might call it, when Britain delivered a letter to Brussels and opened two years of negotiations over the rules of disengagement.

But as Britain tries to bid farewell to its now-estranged partner of 44 years, London faces a different sort of challenge: how a great global city whose residents voted overwhelmingly against Brexit in last summer’s referendum should adjust to an uncertain future governed by principles that feel antithetical to its very being. Brexit has divided Britain from Europe but also divided Britain from itself, with London on one side and much of England on the other (Scotland and Northern Ireland, which also voted to remain, are another story).

To many people in the capital, the vote last year feels like a rejection not just of Europe but also of the values embodied by London, perhaps the world’s most vibrantly and exuberantly cosmopolitan city: Values like openness, tolerance, internationalism and the sense that it is better to look outward than to gaze inward. Even as a sense of melancholy seemed to descend on St Pancras when I walked around the other day, much of the rest of Britain was celebrating.

Here are Britain’s richest people and many of its poorest, living side by side in relative peace. London is stuffed with British landmarks — Big Ben, Buckingham Palace, St Paul’s Cathedral — but also with people comprising 270 nationalities, 8.7 million inhabitants in all.

Brexit has thrown into disarray this great experiment in tolerance. Nobody can predict what the city will look like in 10, 20 or 30 years. If spontaneous travel between Europe and Britain no longer seems so simple, neither does the easy exchange of people, capital, jobs, businesses and languages. Perhaps more significant, it is no longer clear that these are meant to be admirable things, here or anywhere.

“London is a weird place at the moment,” said the writer Nikesh Shukla, whose book The Good Immigrant is made up of essays by nonwhite Britons about a country from which they feel increasingly alienated. He lives in Bristol now but grew up in London, and the city, he says, “feels like a uniquely encapsulated version of what Britain means to me”.

“The government says it’s trying to get the country back, but in the process it’s losing the heart of its people in London,” Mr Shukla said in a telephone interview. “People feel uneasy because there are a lot of futures at stake. These are people who live in the city who contribute to society, who have families, social structures and financial commitments, whose futures are now in doubt.”

I lived in London for more than 15 years, returning home to New York in 2013. The city changed a great deal in that time, and the city I left felt markedly different from the one I found when I arrived. It felt more open, more international, more enthusiastic, more exciting. The food got better, and places stayed open later. My neighbours seemed to come from a United Nations’ worth of countries, our differences somehow erased because we all shared them.

The city also grew a lot richer, which was not necessarily a good thing: The centre of town became all but unaffordable. Russian oligarchs and other members of the world’s ultrarich elite dug up the streets to build subterranean complexes filled with swimming pools and parking garages for homes they planned to live in only a couple of weeks each year.

Europe, which had seemed like a distant concept, suddenly seemed right there on the doorstep. Crowds of French people and then Poles and Spaniards and, later and more contentiously, Romanians moved in. Any time you went to an art gallery or a movie, you saw how British culture was benefiting from European financing. The rise of laughably cheap no-frills airlines made air travel to Europe almost easier than train travel. Tony Blair, prime minister for much of that time, liked to take his vacations in places like Tuscany, in Italy.

London is big and unwieldy and constantly changing. It resists easy definition.

Blair’s election as prime minister, in 1997, ended 18 years of Tory rule and ushered in an era when belonging to Europe felt like something verging on cool. Speaking a foreign language was suddenly, briefly, OK. And then, in 2012, London hosted the Summer Olympics, advertising itself as a city for the world and proving how smoothly and joyfully this polyglot place worked when it put its mind to something, and how unusually well the people who lived here got along.

Here, despite the anti-Muslim, anti-immigrant sentiments that helped fuel the Brexit vote, is London’s first Muslim mayor, Sadiq Khan, whose parents, a bus driver and a seamstress, came from Pakistan. Here are international financiers and playboys, Eurocrats and Eurotrash, as well as economic migrants from Spain and Portugal and other depressed European countries crowding into tiny flats on the edges of town and taking jobs in cafes, on construction sites, in hotels.

“In London I never feel like an outsider, because everyone’s an outsider,” said Mr Paolo Martini, 32, a hairdresser I met in Kentish Town who comes from Brazil and has a Polish wife and a British (by virtue of her birth) daughter. He has lived here for more than a decade; who knows what Brexit will mean for his family?

Part of what makes London different is how closely it all knits together, people from different economic backgrounds as much as different ethnic ones. Every borough has its grand houses and its public housing projects, sometimes right around the corner from one another.

“It’s not just me and you and rich and poor,” said Mr Dara Djarian, 25, a real estate agent in Kilburn whose parents are French and Iranian. He compared the jumbled-up neighbourhoods of London with the more uniform banlieues at the periphery of Paris, centres mostly for Arab immigrants. “Everyone’s all mixed up here.”

I looked down Kilburn High Road from his office and saw what he meant. A Polish delicatessen was next to an Italian restaurant across the street from a traditional London pub beside a Halal butcher shop. There was the Shah furniture store, a classic fish-and-chips place, a ladies-only hairdresser, a luxury bathroom-fixture store, some fancy coffee shops and the highbrow Tricycle Cinema, with a program that appeals to hipsters and cineastes.

“The one thing we don’t actually see a lot of here is English people,” Mr Djarian said. “They’ve moved out to the countryside, or to the suburbs.” THE NEW YORK TIMES