The last time we went to war against a European nation they introduced conscription here, but personally I’m not frightened by the prospect. If we declare war on Spain I expect I’ll fail the army medical.

Maybe I’ll be drafted into the Home Guard instead, and keep a look-out from Whitehaven in case a new Spanish Armada sails up the Irish Sea.

The idea of another war in western Europe seemed far-fetched until the weekend, when former Tory leader Michael Howard raised it as a possibility. It is 35 years, he pointed out, since our previous woman prime minister went to war against a Spanish-speaking country to defend a tiny British colony.

That time was in 1982, when Argentina invaded the Falklands. Lord Howard told an interviewer: “I’m absolutely certain that our current prime minister will show the same resolve in standing by the people of Gibraltar.”

It’s often said that history repeats itself, but I think Howard is stretching this a bit far. The parallels don’t stand up for long.

Spain is a liberal democracy whereas Argentina was a fascist dictatorship. The Spaniards may resent the fact that a chunk of their mainland belongs to another country – just as we might feel miffed if Spain owned a chunk of Cornwall – but they’ve never threatened military action to take it back.

In fact the last time we sent troops to Spain wasn’t over Gibraltar. It was during the Spanish Civil War of 1936 to 1939, when 4,000 Britons volunteered for the Republican cause, fighting to defend democracy against Franco.

And the people of Gibraltar have a much closer relationship with Spain than the Falkland Islanders have with Argentina. There are roughly 30,000 people on Gibraltar, and all but around 200 of them are determined to stay British. Yet a great many cross the border into Spain for work every day and don’t want that border sealed off. That’s why in last year’s European Union referendum 96 per cent of Gibraltarians voted to stay in.

This is yet another problem with Brexit that nobody seems to have thought about. We’ve already seen the complications in Northern Ireland, where the majority voted to stay – by a far bigger margin than the UK-wide vote to leave.

Since the Good Friday Agreement there’s been a lot of cross-border co-operation, to the benefit of both sides of the Irish border, and no-one wants to see it become a “hard Brexit” frontier. Then there’s Scotland. It voted even more decisively to stay, and Mrs May’s tough-talking, Brexit-means-Brexit withdrawal from the single market as well as the EU has given Nicola Sturgeon the perfect excuse for another independence referendum. No-one would put money on it being rejected next time.

Of course Mrs May will make the case against Scottish independence, just as she did at the Scottish Conservatives’ spring conference, saying: “One of the driving forces behind the union’s creation was the remorseless logic that greater economic strength and security come from being united.”

Maybe they do. But if so, doesn’t exactly the same “remorseless logic” apply to that much larger union, the European Union? How can you be for one and against the other? The fact is that the different component nations of the UK are moving in different directions and want different things – and I can’t help feeling it’s approaching its sell-by date.

England may decide it doesn’t want to be dictated to by bureaucrats in Brussels. Perhaps Scotland, Wales, Northern Ireland and Gibraltar won’t want to be dictated to by bureaucrats in London either.