Britain will leave the European Union. Does that mean Scotland will leave Britain?

EDINBURGH, Scotland — The election Thursday sent shock waves through Great Britain and Northern Ireland. The results will bring the return of a substantial Conservative majority, not seen since the days of Margaret Thatcher, with the party securing seats in traditional English and Welsh Labour strongholds. The United Kingdom now appears set to exit the European Union next month and will then enter an arguably more difficult stage of negotiations with Europe after that.

But the picture north of the English border was far different — and the result could launch a long standoff between the Scottish government and the new Conservative powers in London over whether Scotland remains part of the United Kingdom.

While the Scottish National Party, a center-left party seeking Scottish independence, did not replicate the 2015 landslide in which it won all but three Scottish seats in the House of Commons, it did extraordinarily well, taking all but one Labour seat, knocking the Liberal Democrat leader Jo Swinson out of her seat and halving the Conservative count.

The SNP ran on two key messages in this election: a pledge to stop Prime Minister Boris Johnson and Brexit, backing another referendum vote on the E.U., and a call to bolster their mandate for another referendum on Scottish independence. The SNP-controlled government in Scotland held a referendum in 2014, which lost with 45 percent of the vote.

But independence has been kept in the headlines by the SNP's performance in the 2015 election and the Brexit vote, which the party argues provides a mandate for another referendum on independence because Scotland voted 62 percent in favor of remaining part of Europe. The Brexit vote, in the SNP's view, serves as a "material change in circumstances," as outlined in their 2016 Scottish Parliament referendum, and Thursday's result is likely to amplify these calls. Whether the larger Conservative majority at Westminster will make more Scottish voters support independence remains to be seen.

Speaking as the results came in, SNP leader and Scottish First Minister Nicola Sturgeon said that the result was a "clear endorsement Scotland should get to decide our future and not have it decided for us" and pledged to send a letter to Johnson requesting the power to hold a second independence referendum in 2020. The morning after the vote, she held firm: "So, to the prime minister, let me be clear: This is not simply a demand that I or the SNP are making. It is the right of the people of Scotland, and you, as the leader of a defeated party in Scotland, have no right to stand in the way."

The ability to make constitutional changes remains within the preserve of Westminster, unlike other powers devolved to the Scottish government. A legally binding referendum on independence is likely to require a Section 30 order transferring this power from the U.K. to Scotland, as it did in 2014, when the referendum was the result of a negotiation between then-Prime Minister David Cameron and Scottish First Minister Alex Salmond.

In Westminster, the rhetoric of Johnson and his predecessor, Theresa May, is described by colleagues as hyper-unionism, which stresses the maintenance of the union between England, Wales, Scotland and Northern Ireland above all else. During the election campaign, Johnson said he would reject any call for another independence referendum and criticized the Labour Party for their willingness to engage with the issue. His victory speech on Thursday suggested a reinforcement of these unionist themes, emphasizing a "one nation Conservative Government," and Conservative members of Parliament have stressed that the SNP does not have a mandate.

Sturgeon is unlikely to move forward without a formal order allowing her to hold a referendum — unlike separatists in Catalonia, for instance, who held an independence referendum in 2017 without permission from Spain's national government. In interviews during the campaign, she refused to be drawn on what might happen should Johnson refuse to allow an independence vote. The governments in London and Edinburgh now seem set on a collision course, with the possibility of protracted conflict and possibly legal action.

This standoff has implications beyond independence. The U.K. looks set to enter the second stage of negotiations with the European Union, covering a future trade deal after Brexit, with far-reaching implications for Scotland. The Scottish government, joined by the Labour-led Welsh government, wants more formal input throughout the process. But it will be difficult to see how intergovernmental relations may improve if the Scottish and U.K. governments are also involved in a protracted battle over a referendum.

And for the Labour Party, which had a dismal night all around, Jeremy Corbyn will step down as leader soon. Under his tenure, the party attempted to have things both ways on Brexit and Scottish independence. Corbyn pledged renegotiation with Europe but personally remained neutral on whether to have a second Brexit vote. Labour's position on Scottish independence vacillated, causing conflict with leadership in Edinburgh. This was exacerbated by internal turmoil — allegations of anti-Semitism and general poor performance. The party will likely be embroiled in internal conflict for quite some time. And in Scotland, with just one Scottish Labour MP left standing (down from 41 in 2010), the party's future appears uncertain.

Questions can also be raised about the future of the union beyond Scotland. The issue of the Northern Irish backstop to Brexit remains tricky, although it may not get in the way of Johnson's overall plans anymore now that the Conservative government will no longer rely on Northern Ireland's Democratic Unionist Party for support. Calls for extensions and reforms to the agreement allowing Wales to govern itself are likely, too, although notable Conservative victories in key Welsh seats may undercut these demands.