When I moved to Barcelona in 1998, the Catalan independence movement amounted to little more than three men and a dog. Actually, a woman did show up sometimes and the dog was not always there. I’d see them day after day on Las Ramblas at a table draped with a Catalan flag. Few people bothered to give them a second glance.

By the time I left Barcelona for London in 2013, a tiny trickle had become a flood. The year before, on the Catalan national holiday of 11 September, at least 600,000 people had poured onto the streets to demand secession from Spain.

Every year since, polls have indicated that roughly half of Catalonia’s 7.5 million inhabitants wish to live in an independent state. Many more are in favour of a referendum to settle the matter, but the government in Madrid refuses to allow it, saying it would violate the Spanish constitution. The Catalan regional government has nevertheless said that, in spite of the constitution, it will go ahead and hold an independence referendum of its own on 1 October. Madrid has said that this will be an illegal act. On 20 September the Guardia Civil arrested a number of Catalan officials involved in organising the referendum. This marked an alarming escalation of a conflict that previously had not stepped beyond rhetorical hostility.

How did we get here? How can it be that one of the most attractive and seemingly most civilised corners of Europe finds itself in such an ugly mess? Don’t expect to find balanced answers to these questions from the Spanish themselves. The hopelessly irreconcilable nature of the national debate