Instead, getting out of the EU seems likely to require the same readiness to give ground on the part of the departing country as most countries have had to display when seeking to join the EC/EU. If the UK wants a deal, it is likely to be bought through British concessions and the abandonment of some of its initial negotiating aims, rather than large-scale giveaways by the EU27. And it is here that one final parallel with the 1961-3 negotiations becomes worrying. Because just as Macmillan’s ability to make the concessions needed to reach a breakthrough in Brussels was all but destroyed by growing cabinet splits on Europe, dwindling government popularity (1962 was the year of the famous Orpington by-election) and by a Labour opposition increasingly willing to seek party-political advantage through opportunism over the European issue, so too Theresa May’s scope for flexibility seems ever more circumscribed.

The present situation, though, is much more uncomfortable and potentially painful than that of 1963. The implications of failure are far greater. Britain’s inability to join the EEC in 1963 was a hammer blow to Macmillan’s government and a disappointment to many on both sides of the Channel. But ultimately it meant no more than a temporary prolongation of the status quo, and the postponement rather than the end of the UK’s European ambitions. Failure now would be much more serious, confronting the country with all the economic, legal and political consequences of a cliff-edge Brexit. The British government urgently needs to stop repeating the mistakes of its predecessor over half a century ago. A breakthrough in Brussels is a national necessity – even if achieving it requires awkward and painful climbdowns.