Nearly three years after the United Kingdom voted in a referendum to leave the European Union, Brexit continues to wreak havoc on British politics, and the country remains a member state of the bloc. Last week, Prime Minister Theresa May announced that she will resign, on June 7th, after failing to secure a deal with Europe around the terms of British departure. A leadership contest is already under way, with Boris Johnson—the clownish former mayor of London and former Foreign Minister—the most likely candidate. Johnson favors a “harder” Brexit than May and has even threatened to leave Europe without any sort of deal, potentially sending the British economy into chaos. Meanwhile, Jeremy Corbyn, the left-wing leader of the Labour Party and a longtime Euroskeptic, has resisted the pleas of fellow-Labourites to call for a second referendum.

Election results for the European Parliament were announced on Sunday, with far-left and far-right parties all over the continent gaining strength. In the United Kingdom, which a year ago was not even expecting to have a vote in these elections, Nigel Farage—the former UKIP leader and the politician most associated with the Leave campaign—saw his new Brexit Party emerge with a plurality of seats. Labour—caught between its pro-Remain base and some members from seats that voted Leave—lost support to the Green Party and the Liberal Democrats, and did very poorly in Scotland, where voters are staunchly pro-Remain.

To discuss what these election results mean for the U.K., and the future of Europe, I spoke by phone with Helen Thompson, a professor of political economy at the University of Cambridge and a panelist on the British weekly podcast “Talking Politics.” During our conversation, which has been edited for length and clarity, we discussed why the Brexit Party was able to achieve so much success, why Corbyn is struggling with voters who care about the environment, and the existential dilemmas facing the two main parties.

How much do these results in the U.K. seem similar to what is going on across Europe, and how much do you think what is happening in Britain is unique?

I think it’s pretty hard to make too many comparisons between Britain and the other member states, because, the way things stand at the moment, Britain’s supposed to be leaving on October 31st. The one thing in common is that there is fragmentation across party systems in a number of countries. Indeed, Britain is now actually following what happened in other countries, rather than the other way around, in that the urban younger left voters are deserting center-left parties, often for the Greens. And so it isn’t just the Liberal Democrats who’ve benefitted here from the Remain defections from Labour. It’s the Greens, too.

And the Greens have not really had much of a voice in the Brexit debate. They’ve had a clear position [in favor of remaining in the E.U.], but they haven’t been able to cut through, really, in terms of having a distinctive message. I think that their ability to win votes is both because of the environment issue itself, but also because we are seeing young center-left voters very disillusioned with social democratic, traditional center-left parties and looking for something else.

That’s interesting, because the Corbyn project has been to reinvent the Labour Party as more of a left party, rather than the more centrist, center-left Party of the past several decades. Does the fact that he failed so miserably to do that in this election suggest that he got tripped up over Brexit, or does it suggest a larger failure?

I think he got tripped up over Brexit. It’s reasonably clear that Labour lost Remain voters to the Liberal Democrats and the Greens, particularly in the larger cities and in some parts of the South, and that it lost Leave voters to the Brexit Party in the Midlands and the North. So Corbyn’s desire to play both sides of the Brexit divide has really fallen apart at this election.

I think, separately from that, there is growing discontent, which is fuelled by Brexit but isn’t only about Brexit, in a section of the voters that Corbyn initially mobilized: relatively young urban voters. And I think that that’s got another aspect to it, which is the disillusionment with his leadership about the anti-Semitism issues. So you had people who were willing to give Corbyn the benefit of the doubt because they absolutely wanted to oppose the Conservative Party, but have found sticking with Corbyn, in the face of these anti-Semitism issues, more difficult than it previously was. I think if you go back to his difficulties last summer, when you started to see the project under considerable strain, that actually was at least as important as Brexit. I’d say right now that Brexit is most important, but I don’t think it’s actually the only thing that’s going on in terms of Corbyn’s ability to hold the movement together.

I think the environment issue is actually quite interesting in another way, and that is just because Corbyn’s not a natural for environment questions. He and the people around him were very much formed by class-based politics domestically and by the anti-colonial, anti-U.S. foreign-policy politics of the nineteen-seventies and the nineteen-eighties. They’re happy to talk the language of environment politics, but it’s not where they’re coming from. Whereas the defecting younger voters that they mobilized are very responsive on green issues.

There have been post-result rumblings that Corbyn will come out more squarely for a second referendum. But, although the results suggest that he lost a lot of Remain voters, he also lost some Labour voters, many of them in the North, who were in favor of Brexit, right?

Yeah, I think he’s going to come under a lot of pressure to move closer to a second referendum, because the people in the Party who have been pushing in that direction for some time tend to be the dominant Labour voices in the media. And they have the people from the People’s Vote campaign [a popular movement for a vote on the final Brexit deal] pushing very hard in that direction. But it’s also clear that there are individual M.P.s—not just from the North but also from the Midlands—who are very concerned about the Party going down that direction, and quite reasonably so.

Now, you could argue that Labour’s got more voters to lose on the Remain side than it has on the Leave side. That is quite probably true. The problem is that, when you look at the geography for the general election, the seats that Labour needs to win to have any chance of forming a parliamentary majority—if you leave the Scotland issue aside, where Labour’s just been hammered—are more Leave-looking seats than they are Remain-looking seats. While shifting over to a second referendum position might maximize the number of votes that Labour can possibly win in absolute terms, it comes with considerable electoral risks.

What did you make of the Brexit Party winning a plurality?

First of all, it is an existential threat to the Conservative Party, unless the Conservative Party can have Britain leave the European Union, if not exactly on October 31st, then reasonably quickly afterward. The Conservative Party is now in a position where, for it to make a recovery, Britain has to leave the European Union. The second thing is that the Brexit Party is not run like a political party. It is a more slickly organized than UKIP ever was. Nigel Farage has sort of reinvented himself. This is a more effective Farage than the man who ran UKIP. And they did really quite a striking job of putting together a demographically diverse group of candidates, something that UKIP was never able to do at all. And so I think that if this Party sticks around, because Brexit doesn’t happen, then it’s got more legs than UKIP would have had in circumstances in which Remain had won the referendum in 2016. But if the Conservatives were able to take Britain out of the European Union, then I think that it would wither away pretty quickly, if there was no deal in the departure. It would be a bit more complicated in the case of Britain leaving with an agreement.

What, if anything, do you expect the Brexit Party to do in the European Parliament?