On Jan. 31, workers solemnly removed Union Jack flags from the European Parliament and European Council buildings in Brussels, Belgium. Later that evening, the United Kingdom, which consists of England, Wales, Scotland and Northern Ireland, officially left the European Union.

The EU traces its origins to the European Economic Community, founded in 1957. The United Kingdom entered the EEC in 1973. Over the years, the EU has expanded to 27 countries, including several that had been in the Soviet Bloc during the Cold War. In 1999, 19 of those countries (not including the U.K.) adopted the Euro as a common currency.

In 2016, the United Kingdom held a contentious referendum on withdrawing from the EU that resulted in 17.4 million people, 52% of those who voted, agreeing that the U.K. and the EU part ways.

This kicked off a period of political instability with Prime Minister David Cameron, an EU supporter, resigning after the referendum, leaving his successor, Theresa May, to negotiate Britain’s departure. She survived two no-confidence votes, reached an agreement with Europe, and then stepped down. Current Prime Minister Boris Johnson, a former mayor of London and Brexit supporter, was elected in July.

Erik Linstrum is a University of Virginia historian of modern Britain in its imperial and global contexts. His research explores the politics of knowledge and the circulation of information, with particular interests in science and technology, war and violence, and the long history of decolonization. His first book, “Ruling Minds: Psychology in the British Empire,” won the George Louis Beer Prize of the American Historical Association for the best book of the year in European international history.

In a discussion with UVA Today, Linstrum explores how Brexit came to be, along with what may be ahead for the British Isles.

Q. As a historian of Britain and modern Britain, how do you view Brexit?

A. For me, as a historian of empire, it is hard not to be struck by the currents of imperial nostalgia.

Britain’s relationship with Europe has always been uneasy, because Britain has seen itself as a global power, as a maritime power, an imperial power, with its destiny across the ocean and on continents other than Europe. And it is no coincidence that Britain joined what was then the European Economic Community at precisely the moment that its empire was dying. (It first applied in 1961 and ultimately joined in 1973.)

In the headlines after the [pro-Brexit] referendum vote in 2016, some of the Brexit-backing, right-wing tabloids said things like, “The Empire Strikes Back” and “Britain’s Resurgence.” You also have British civil servants talking about their vision of trade deals beyond Europe, going back to the former colonies of Canada, Australia and the United States, as well as Africa and Asia, and using the shorthand of “Empire 2.0.” It is hard not to see a longing for an era in which Britain had a global presence that was not constrained, was not limited by Europe.

Irish journalist Fintan O’Toole makes a point of what he calls the “strange sense of imaginary oppression” that motivated a lot of the Brexit movement. In an imperial culture, there are only two kinds of states, the colonizer and the colonized, the ruler and the ruled. In the European context, you technically have coequal states, but it was very clear that Britain was not the ruler, was not calling the shots in Europe. If there is any dominant force in Europe, it is of course Germany.

Q. Looking at this as a historian, where do you see it going?

A. Most pressing is the potential for Brexit to accelerate the break-up of the United Kingdom.

The Brexit vote was not uniformly distributed across the United Kingdom. The vote in the U.K. overall was 52% leave and 48% remain. But in Northern Ireland, it was 56% remain, and in Scotland, you had an even bigger majority of 62% to stay in the EU.

These are huge regional variations at a moment when you already have some strain in the U.K. as a whole. Since the late 1990s, there has been a policy of devolution, where the constituent nations of Scotland, Wales and Northern Ireland have their own parliaments or national assemblies, and that has led to a growth of sub-national identities, with Scottish nationalism as the most pronounced example.

For the Scottish National Party, Brexit has been a gift. It has shown that the strong will of the Scottish people to stay a part of the EU can be overridden by mostly English votes. That is a real thumb in the eye to them and it explains why, in the years since the Brexit referendum, the Scottish National Party has continued to gain strength and now possess the overwhelming majority of Scottish seats in Parliament at Westminster.

Q. How much of that vote was Scotland wanting to remain in Europe and how much is it didn’t want to be linked to England?

A. Probably a bit of both.

There is a strong streak of European identification in Scottish political culture that you don’t have in English political culture. Part of that goes back to devolution, which allowed for the growth of a separate political identity in Scotland that you could not have had before. There is stronger support for the welfare state and redistribution in Scotland than you get in England; the reasons for that are complex, but have to do with the heavily industrial orientation of the Scottish economy through the mid-20th century and the dual impact of deindustrialization and Thatcherism in the 1980s.

Since the discovery of North Sea oil off the Scottish coast in 1969, moreover, nationalists have encouraged the idea that Scotland can model itself on the Nordic countries. So you can have prosperity from the oil wells and you can have a strongly redistributionist state.

The other piece of Brexit, I think, is that it was motivated by a specifically English nationalism more than a broader British nationalism. The decisive votes for Brexit came from England, particularly the parts of England excluding London, other large cities like Liverpool and Manchester, and university towns like Cambridge and Bristol. (Wales also voted narrowly to leave.) The votes of so-called “Middle England” were really decisive and that cut across more prosperous areas, more deprived areas, rural areas and certainly a lot of smaller cities.

English nationalism has a fraught history because of its intimate links with the far right, racism and anti-immigrant sentiment, going back to the National Front, which is more than a half-century old now and was founded by self-proclaimed fascists who despaired at the end of the British Empire. There is an argument for seeing Brexit as the expression of a frustrated English nationalism that had long been confined to the political fringe.

Q. With Brexit and questions about the border between Northern Ireland and the Irish Republic, are the Northern Irish voters afraid they will end up rejoining the Republic?

A. It is striking the degree to which the pro-Brexit side paid absolutely no attention to the implications for Ireland in the run-up to the 2016 vote.

There is a long tradition of British ignorance, apathy and contempt for Ireland. What is so extraordinary is that the official name of the Conservative Party in Britain is the Conservative and Unionist Party. A commitment to the union between the United Kingdom of Great Britain and Northern Ireland has been central to what it has meant to be a British Conservative for a long time. And, of course, one of the great achievements of British diplomacy and politics in the past few decades has been the Good Friday Agreement of 1998 [which ended much of the political strife and paramilitary violence between the Unionists, who want to remain part of the United Kingdom, and the Republicans, who want to reconnect Northern Ireland with the Irish Republic].

The Northern Ireland vote was pro-remain by a pretty wide margin, but it did break down on sectarian lines. Catholics voted by a very wide margin to remain and Protestants in the north voted to leave by a somewhat narrower margin. There is a historical antipathy to Europe from Ulster Protestants for a lot of reasons, but I think the desire to maintain a distinct identity from the heavily Catholic Republic – and perhaps fear about the potential for reunification at some point in the future – was part of it.

The big holdup in finalizing a withdrawal agreement with the EU over the last year or so was what was going to happen to the border on the island of Ireland, because you now have a situation where the north is going to leave the EU with the rest of the United Kingdom, while the Republic of Ireland remains in Europe. How do you then have the open, demilitarized border that was a big achievement of the Good Friday Agreement?

While the votes of the Democratic Unionist Party, a Protestant party in Northern Ireland, were essentially keeping the Conservatives in power at Westminster in the last Parliament, the government was unwilling to sell Ulster out, so they came up with this tortured logic of a “backstop” that would allow Northern Ireland to be kind of in and kind of out at the same time.

Now that the Conservatives have a bigger majority, they have essentially sold the Ulster Protestants out, and agreed to a relatively open border on the island of Ireland at the expense of a harder border between Ireland and the rest of the United Kingdom. They are trying to say Northern Ireland is still going to be a constituent part of the United Kingdom, but in practice new divisions are opening up.

The long-term demographic reality is that the Catholics are beginning to outnumber Protestants in Northern Ireland. This is now showing up politically, with Republican parties outnumbering Unionist parties for the first time among members of Parliament elected from Northern Ireland, which is a significant change.

Then you have this extraordinary recent election in the Republic of Ireland in which Sinn Féin has broken into the national political scene in a major way. While the other parties have maintained a nominal commitment to an eventually, sometime-in-the-future united Ireland, Sinn Féin would like to see that timetable pushed forward and is seeking a referendum. The relevant provision of the Good Friday Agreement is that you need the agreement of the people in both the south and the north, so Sinn Féin is pushing for a referendum on both sides of the border.

Partly because of Brexit, partly because of those demographic changes I mentioned, it is not at all clear that a referendum wouldn’t pass in the north if you had it. And if it doesn’t pass now, possibly in five or 10 years, it could.

Q. What does all this mean for the other English-speaking elements of the former Empire?

A. The hope of the Brexiteers that there is a rich world of trade deals awaiting the United Kingdom when it leaves the EU. I am skeptical about that.

The EU is, and still going to be, by far the most important trade partner for the United Kingdom. Something like half of its exports go to the EU. Only about 15% of U.K exports go to the U.S.

Even if they did secure a really advantageous trade deal with the U.S. – setting aside Canada and Australia, which don’t crack the top 15 of U.K. export markets – it is not clear that is going to have any kind of revolutionary impact. They are still going to have to figure out some kind of deal with the EU and they now face a dilemma.

If they want continued seamless access to EU markets, they are either going to have to accept a lot of EU rules and regulations, which they no longer have any say in creating, or they are going to have to say goodbye to a really important part of their economy, like financial services in the City of London. And if they accept EU rules and regulations wholesale, they would also have to accept things like free movement, which was a big reason why Brexit happened in the first place.

So I don’t think there is going to be a breakthrough anytime soon. This is a case where hazy nostalgia for the unity of the English-speaking peoples of the world is maybe clouding the economic and diplomatic reality a bit.

Q. Does Britain survive this or fade into the setting sun?

A. Britain will survive. But the illusions of grandeur which maybe helped to produce this outcome in the first place are going to have to face some kind of reckoning with reality. When this cornucopia of lucrative trade deals fails to realize itself, I think the likeliest scenario is that British Prime Minister Boris Johnson and the Tories are going to backtrack on a lot of the promises made in the referendum.

Clearly economic growth has already been slowing, partly because of Brexit, and you see things like Japanese car manufacturers who had plants in relatively deprived areas of the U.K. closing up shop and moving to the continent because they are no longer going to have seamless access to European markets. So you are going to see a lot of manufacturers and maybe also banks moving to Dublin, to Paris, to Frankfurt.

There is going to be an economic bite, it is just a question of how powerful it is, and I think Britain is going to find that there was a way that Europe allowed it to punch above its weight. The sentimental idea of the Special Relationship might help at the margins at getting attention, getting aid, getting influence with the United States, but I think that the drama of the trade negotiations will show, over the next year, that economic interests ultimately matter more.

One irony of Brexit, with all its grand dreams of a resurgent Anglo-world, is that it is going to make Britain a much less valuable ally for the U.S.