By Lord Kerr of Kinlochard

AT Glasgow Academy I wasn’t as good at history as Neil MacGregor or Niall Ferguson. But I learned enough to spot a historic mistake, and Brexit would be a huge one.

As Ambassador in Washington, I found that President Clinton listened to British advice partly because he recognised British influence in Brussels, and knew that a common US/UK position had a good chance of becoming a US/EU position. It was a virtuous circle : by being strong in Brussels we became stronger in Washington, and better placed to help our friends in Canberra and Cape Town, Ottawa and New Delhi. None of them would welcome Brexit.

At Glasgow Academy we walked to classes past the inscribed names, more than 300 names, of former pupils killed in the First World War. We learned how division in Europe can bring heartbreak to Scotland. Fifty years ago, as a young diplomat in Moscow, I watched Brezhnev’s tanks rumble into Prague, deposing the Czech government. On November 9 it will be 29 years since the Berlin Wall cracked, releasing hopes of a Europe again whole and free. I was at the Edinburgh European Council in 1992 when we charted for the new democracies of Central Europe a route to the EU membership they so badly wanted. Brexit puzzles and saddens them. The price of liberty is eternal vigilance : the Russians – occupying the Donbas and Crimea, Abhazia and Ossetia – still threaten their neighbours. History should have taught us the perils of insular disengagement.

A week ago, at a conference in Glasgow City Chambers, I heard the economic experts explain how Brexit would hurt the Scottish economy, cutting incomes and jobs. The picture was bleak : taxes up, living standards down. EU membership has been good for Scotland, attracting investment from across the world, with the single market programme knocking down barriers to Scotland’s exports of goods and services. Our universities have gained disproportionately from EU Research funds: we get far more out than we put in. The Regional Fund, invented under a Scottish Commissioner, George Thomson, and modernised under another, Bruce Millan, has pumped resources into the Highlands and Islands.

No wonder the polls show that Scots, given the chance, would today vote against Brexit even more overwhelmingly than they did in 2016. And they want to be given the chance – 61 per cent of Scots, and a rising majority in the UK as a whole, want a People’s Vote on the outcome of the current negotiations. So it was good to see the First Minister say on Sunday that SNP MPs would back such a vote when the Westminster crunch comes. How Scots MPs vote could be decisive.

At Glasgow Academy I was taught that the key democratic principle is informed consent. We are better informed than we were in 2016 : the negotiations have proved the Leavers’ prospectus false. As John Major said 10 days ago, “the public should be allowed to vote again, so that, this time based on fact not fantasy, they can re-endorse their position, or decide differently.” Brezhnev’s “one man, one vote, once” is not our way. It was David Davis who said, back in 2012, “the democracy that has lost the right to change its mind has ceased to be a democracy”.

Scots of all parties and none should rally behind the People’s Vote cause. Glasgow and Edinburgh have long been great European cities. We mustn’t let short-sighted Little Englander prejudice hem us in.

My grandfather was on the Somme. My parents met in 1930s slump Glasgow : their Hillhead home was blitzed in 1941. We should heed the lessons of history.

The author, an Independent member of the House of Lords, was Ambassador to the EU and US and FCO Permanent Secretary. Subsequently Secretary-General of the European Convention, he drafted Article 50, the procedure under which the UK is now negotiating Brexit.