The certainty that Brexit will take place brings into sharp relief the ultimate choice facing Scotland – the UK union or the European Union

Last month's UK general election will undoubtedly be remembered for the Conservative Party's historic victory and the long-awaited clarity on Brexit. Yet the vote was not uniform across the UK.

In Scotland, the Scottish National Party (SNP) secured an even more emphatic result, taking 47 of the nation's 59 Westminster seats.

In contrast to their success in England, the Conservatives lost half of their seats in Scotland, dropping from 13 to 6 MPs.

Scotland's Europeanism was reaffirmed once again in this latest vote. An extraordinary 90 percent of Scotland's new MPs are pro-European and favour remaining in the EU.

The trend is not new.

In the European Parliament elections, 71 percent of the popular vote in Scotland went to pro-EU parties. The Scottish electorate also voted decisively for Europe in the UK's 2016 EU referendum.

December's election has proven that Scotland and England are on firmly different political paths. While England pursues its course of Brexit euroscepticism, Scotland has continued its tradition of mainstream Europeanism.

Despite rejecting Brexit in multiple democratic events, Scotland will nevertheless leave the EU with the rest of the UK. That will be an occasion of deep sadness and regret.

The certainty that Brexit will take place brings into sharp relief the ultimate choice facing Scotland – the UK union or the European Union. Those who had wanted Scotland to remain both in the UK and in the EU will eventually have to decide which union they favour.

Scotland's European roots run deep, and many voters have increasingly concluded that, between the UK outside the EU and an independent Scotland inside the EU, they choose the latter.

Independence is the primary issue in Scottish politics, and the question of a further independence referendum has been on the table since the UK's vote to leave the EU.

In/Out, Either/Or

As often occurs in such debates, two arguments are currently running in parallel – whether Scotland should become independent, and whether a referendum should be held.

Having secured 80 percent of Scotland's MPs, the SNP has taken that victory as proof that the Scottish electorate wants a new referendum.

SNP leader and first minister of Scotland Nicola Sturgeon made the formal request to the UK government at the end of last year for the legal power to hold a referendum.

UK prime minister Boris Johnson has however made plain his opposition to such a referendum. While the UK government has yet to give its official response, it would never actively encourage a plebiscite.

Should London agree to transfer the referendum power, it would stem from a mandate from the Scottish electorate, not its own preferences.

The Scottish government wants to hold the referendum this year, potentially making time quite short. In the weeks ahead, it will bring to bear all the political pressure it can muster to persuade the UK government to acquiesce.

The heart of the argument on whether to hold another independence referendum is the question of what constitutes a mandate for one.

In 2011, the SNP won an outright majority in the Scottish parliament, paving the way for the 2014 referendum. At the moment, the SNP is a minority government.

However, both the SNP and the Scottish Greens support independence. Taken together on this issue, the Scottish parliament has a pro-independence (and pro-referendum) majority.

No consensus exists on what represents a mandate. Does a single party need to have won a majority with a specific pledge to hold a referendum? Or is a majority of the parliament sufficient?

The next Scottish election is scheduled for May 2021. If the issue is not resolved by then, and the SNP wins a majority, the case for a referendum would become increasingly undeniable.

The European dimension will be a major part of Scotland's next independence referendum. The UK's exit from the EU changes fundamentally the prospectus from 2014.

Significant issues will include the timeline for EU accession and the border between Scotland and England. A more measured and honest debate will be needed.

The currency will once again be totemic. Despite its pro-Europeanism, joining the euro is remarkably unpopular in Scotland. Public opinion on Nato is also mixed, and defence will be another point of debate.

After Brexit, the great risk is that Scotland becomes gradually disconnected from the EU and fades into irrelevance.

Scotland will have to work hard to maintain its European connections and demonstrate that it still has contributions to make to the future of Europe.

For its part, the independence debate needs greater realism on what being a European small state involves.

Scotland's pro-European politics will endure, even once Brexit has taken place. Its constitutional future remains to be determined.