1. An Englishwoman, a Welshwoman and a Scotswoman sit next to each other on TAP Portugal’s evening flight from Lisbon to London on 3 September. What are they required to do on arrival at Heathrow airport?

2. From a Welsh perspective, which of these lovely islands is the odd one out: Crete, Madeira or Tahiti?

3. You live in Carlisle. A friend from across the border in Dumfries invites you along for a cup of tea to hear about the Greek holiday you’ve just returned from. What do you say?

The answers in a moment. First, the context. The UK, its travel industry and millions of holidaymakers are rapidly sinking into a quarantine quagmire as the government in Westminster seeks to limit coronavirus cases coming in from abroad.

Since June, when quarantine was imposed on arrivals to the UK from every country in the world except Ireland, the four nations have been largely singing from the same self-isolation hymn sheet.

Scotland, Wales and Northern Ireland have been persuaded by central government to adopt an all-or-nothing approach to quarantine.

A country must be either high risk or low risk, with no differentiation between parts of the nation. And if it is high risk, there is no viable alternative to 14 days of self-isolation.

But on Thursday, everything started to unravel. After what I understood was a bad-tempered conference call, the devolved administrations in Scotland and Wales went their own way. Or ways.

Scotland put all of Portugal on its no-go list, imposing quarantine from 4am tomorrow, and gave Gibraltar a yellow card.

The Welsh government went several steps further, adding Gibraltar, six Greek islands and Portugal to its self-isolation list – but subtracting Madeira and the Azores.

England and Northern Ireland changed nothing.

The resulting shambles is summed up by the answer to the first question.

The Englishwoman could do what she liked, for example go to the pub. The Welsh resident was required to go straight home and stay there for two weeks. And unless the Scotwoman had a fast car waiting to whisk her north of the Anglo-Scottish border by 4am on Saturday, she faced the same quarantine obligation.

The second answer: Madeira. Welsh residents returning from the other two islands must self-isolate. Contrary to the UK government, the health minister in Cardiff believes quarantine can be targeted on locations where particularly high infection rates have been detected. If Portugal’s islands present a negligible threat – which has been the case throughout this miserable pandemic – then they, and would-be holidaymakers, should not be penalised.

Question three shows what this disarray is doing to the Union. No resident of England (or Northern Ireland) who has been in Greece (or Portugal) in the last fortnight can venture into Scotland. In view of this internal travel restriction, the invitation must be politely declined.

This tangle of geo-political contradictions is wrecking confidence among travellers, alienating host nations and destroying jobs.

If the figures who are directing this fiasco are to salvage any shred of respect, they must immediately stop playing the blame game.

Remove the blanket quarantine measures that are smothering the travel industry. Agree on proportionate, targeted restrictions in response to known virus hotspots. And end the “English exceptionalism” that insists testing travellers is worthless.