Leaving the European Union is not the only split British Prime Minister Boris Johnson has to worry about.
Johnson's commanding election victory this week may let him fulfil his campaign promise to "get Brexit done," but it could also imperil the future of the United Kingdom of England, Scotland, Wales and Northern Ireland.
Scotland and Northern Ireland didn't vote for Brexit, didn't embrace this week's Conservative electoral landslide -- and now may be drifting permanently away from their neighbours.
In a victory speech Friday, Johnson said the election result proved that leaving the EU is "the irrefutable, irresistible, unarguable decision of the British people."
In Scotland, 48 of the 59 seats were won by the Scottish National Party, which opposes Brexit and wants Scotland to become independent of the UK SNP leader Nicola Sturgeon said her party's "emphatic" victory showed that "the kind of future desired by the majority in Scotland is different to that chosen by the rest of the UK."
Johnson's office said the prime minister told the Scottish leader on Friday that "the result of the 2014 referendum was decisive and should be respected."
The Scotsman newspaper summed up the showdown Saturday with front page face-to-face images of Sturgeon and Johnson: "Two landslides. One collision course."
Mark Diffley, an Edinburgh-based political analyst, said Sturgeon "has said that she doesn't want a Catalonia-style referendum. She wants to do this properly."
Diffley said the size of the SNP's win allows Sturgeon to argue that a new referendum is "the will of the people."
Sturgeon said that next week she will lay out a "detailed democratic case for a transfer of power to enable a referendum to be put beyond legal challenge."
"By refusing to concede it, Johnson has ironically become a recruiting sergeant for increased militant nationalism."
"I think there is a good chance there will be a united Ireland within 10 years."