Back in the 1950s, a reason for the antagonism between Andalusia and Catalonia was that Andalusia didn't take kindly to Catalan jibes about migrant workers being cave dwellers. As a collective, Andalusian labourers who went to Catalonia were subjected to what amounted to racist slurs and stereotyping.

There may, however, have been some basis to the cave dweller insult. Caves, if money was short (and it would have been), did at least offer a form of accommodation, as the early hippies in Ibiza in the 1960s were to also discover. But these were caves as caves had been intended to be. They hadn't been converted and made habitable.

Some seventy years on from those days of insults, the Catalonia government has recognised that cave dwelling offers a potential source of revenue by being properly regulated. The government's latest rules allow caves, which obviously have to be habitable and to meet certain standards, to be made available as holiday rental accommodation. And caves aren't alone. There are also, for example, tree houses and dry stone huts. Regulated and legalised, they all offer tax revenue, which includes the Catalonia tourist tax.

Over recent years in Majorca, there have been weird examples of holiday rental popping up on Airbnb; weird and not legal. But now that Catalonia has opted for the cave route, might the Balearic government follow suit? Very doubtful. Caves and tree houses would inflate the number of tourist accommodation places; and that would never do.