A striking feature of the UK’s referendum on EU membership has been the failure of its leading figures to learn from the experience of Britain’s last flirtation with constitutional upheaval, Scotland’s 2014 independence plebiscite.

Once again, predictions of economic disaster were not enough to swing voters decisively behind the status quo in the run-up to polling day.

For the second time in less than two years, David Cameron, prime minister, went into referendum day with his and his country’s political future hanging precariously in the balance.

The fact that Scotland did in the end vote by a 55-45 per cent margin to stay in the UK partly explains why opponents of Brexit reached for the 2014 political playbook, recylcing it battle-tested tactics and slogans. Mr Cameron claimed that remaining in the EU offered the “best of both worlds”, for example, a line first used to describe Scotland’s status in the UK.

But the Scottish referendum was far from an unambiguous victory for supporters of UK unity. Majorities in the cities of Glasgow and Dundee actually voted for independence. That would have been almost unthinkable when the prime minister approved Scotland’s plebiscite back in 2012.

As for the dire warnings of financial pain, Campaigners for Brexit were able to blunt the effect of such gambits by portraying them as part of a “Project Fear”, just as Scottish Nationalists had before them.

As in Scotland, worries about the economy may be enough to put Remain over the referendum line. But what about enduring sentiment? The relentless focus on financial risk has left little room for a more positive case about Britain’s EU membership.

Perhaps the most important lesson from Scotland, however, was the naivety of expecting a referendum to take the sting out of a long-running political debate. An overwhelming rejection of independence might have at least pushed the issue down the political agenda. This year’s hard-fought campaign over EU membership has instead turned the Conservative internal feuding that pushed Mr Cameron to promise a plebiscite into open civil war.

By their nature, referendums can be divisive, forcing voters to make a binary choice on an issue they might not previously have taken an established view on or even seriously considered

By their nature, referendums can be divisive, forcing voters to make a binary choice on an issue they might not previously have taken an established view on or even seriously considered. And Scotland showed that many such voters these days feel little instinctive support for the status quo or trust in the mainstream political establishment.

The campaign troubles of the EU Remain camp would likely have been even worse if its Leave rivals had found a way to match the positive tone struck by Scotland’s broader pro-independence movement. Doing so would have helped win over waverers put off by many Brexiters’ antipathy to immigration and foreign influence.

Senior UK politicians expected the Scottish referendum to kill dreams of independence for a generation at least. Instead it energised the Scottish National party and propelled it to landslide victories in the UK and Scottish parliament elections. Even though an oil price slump since 2014 has wrecked the SNP’s rosy fiscal case for independence, support for separation remains strong. None of the polls tracked by ScotCen Social Research since the referendum show backing for independence below 45 per cent when ‘don’t knows’ are excluded.

If the UK votes to stay, a campaign centred so heavily on Brexit’s costs and risks is likely to leave public support for EU membership highly conditional at best. Likewise, a vote to Leave will probably trigger years of bitter debate over the terms of UK engagement with its former EU partners on everything from trade and freedom of movement to financial regulation.

Just as the 2014 rejection of Scottish independence was only a provisional victory, the battle over the UK’s role in Europe will not be ended by Thursday’s result. British politicians may well end up having more opportunities to learn from referendum experience.

mure.dickie@ft.com