Thursday, May 6 is a date that could give British Prime Minister Boris Johnson more sleepless nights than his new baby in Downing Street. It’s the day when a tiny country may begin a process to end the UK. The population of Scotland is just five million in a UK of 67 million. But the devolved Scottish Parliament in Edinburgh will hold elections that will be seen as a guide as to whether Scots want a second referendum on independence, with profound consequences for the EU, too. The <a href="https://www.thenationalnews.com/opinion/uk-independence-debate-is-not-over-1.239922">first Scottish referendum in 2014</a> ended with just 45 per cent of voters saying "Yes" to ending the UK as it has been constructed since the Union of the Scottish and English Crowns four centuries ago, in 1603. That 2014 vote was seen as a once-in-a-generation event, although First Minister Nicola Sturgeon had one caveat. Scotland, she said, would want to vote again on independence if there was what she called a "material change" in circumstances. And now there is, <a href="https://www.thenationalnews.com/world/europe/post-brexit-trade-deal-with-eu-passes-into-uk-law-1.1138055">thanks to Brexit</a>. That’s because Scots were promised in 2014 that voting "No" to independence was the only way to stay in the EU. That has proved to be wrong. In fact, precisely the opposite has been the case. Scotland has been taken out of the EU against its will. There is considerable resentment about this, so much so that for most of the past six months in repeated <a href="https://www.thenationalnews.com/world/europe/movement-for-scottish-independence-gathers-pace-1.1152765">opinion polls</a>, voting Yes to independence consistently reached 50 per cent or more. But then came <a href="https://www.thenationalnews.com/opinion/comment/scotland-s-latest-political-intrigue-could-slow-its-march-to-independence-1.1175492">a bizarre civil war</a> within the ruling Scottish National Party between Ms Sturgeon, the current leader, and Alex Salmond, her predecessor. In the past few days, it looked as though that civil war was at an end and Ms Sturgeon had won. She was <a href="https://www.thenationalnews.com/world/europe/ethics-inquiry-clears-scotland-s-leader-nicola-sturgeon-of-wrongdoing-1.1189299">cleared of wrongdoing</a> by a respected independent inquiry. But then Mr Salmond – who once wrote a book about Scottish independence titled <em>The Dream Shall Never Die</em> – proved that this grudge may never die. He founded a rival pro-independence political party called by the old Gaelic name for Scotland, Alba. So what happens next? No one knows exactly. It's in the hands of Scots voters who have a big choice to make, not just between parties favouring the union of Scotland within the UK and other parties arguing for independence, but between various flavours on both sides. Yet what makes this more than <a href="https://www.thenationalnews.com/world/europe/scottish-leader-nicola-sturgeon-denies-she-misled-parliament-over-alex-salmond-claims-1.1187095">a grudge match</a> between factions in a small country on the edge of Europe is that all this bickering and bitterness may lead to a big turnout of voters on May 6. If pro-independence parties together poll more than 50 per cent, Mr Johnson will be faced with a very dangerous dilemma. Does he refuse Scotland a second independence referendum, as he insists he will, acting undemocratically and irritating Scots even further? Or does he agree to a referendum, perhaps some years in the future, which he might lose – and, in the meantime, showering Scotland with more political powers and even more money? But that risks a backlash from his own supporters in England. Either way, we are now entering a new fight for the union of the UK, and with a very serious twist. In 2014, when Scotland voted No on independence, the EU was quite negative on whether the Scots could become members of the 27-member bloc. Spain, in particular, was alarmed. Would Scottish independence, rewarded with EU membership, encourage Catalans to do the same and split from Spain? Spain could veto Scots' EU membership to discourage others kinds of separatism. But now, of course, since Brexit, Scotland would not be “breaking away” from an EU country. EU watchers say the mood has changed in Brussels and Scotland would be strongly welcomed as a warning to other countries of the perils of leaving the bloc. But if you still doubt the potential importance of a few hundred thousand Scottish voters in a small country on the edge of Europe changing their minds about independence, then don’t take my word for it. George Osborne, the former UK chancellor of the exchequer, said of the 2014 independence vote that he and David Cameron, the then prime minister, fretted that if Scotland broke away then their government would go down in history as a disastrous failure for “losing the Union". And if Scotland now heads towards independence in 2021, Mr Osborne says this eventually could “represent the end of the United Kingdom". "The rest of the world would instantly see that we were no longer a front-rank power, or even in the second row," he added. "We would instead be one of the great majority of countries who are on the receiving end of the decisions made by a few, subject to the values of others. We would become another historically interesting case study in how successful nations can perform unexpected acts of national suicide.” Mr Osborne suggested that Mr Johnson, his fellow Conservative, could go down in history as the worst British prime minister ever. We will know more within a few weeks. <em>Gavin Esler is a broadcaster and UK columnist for The National</em>