What if Britain treated Scotland the way Spain treats Catalonia?

Imagine that, instead of agreeing terms with Alex Salmond on an independence referendum, David Cameron had prosecuted him. Suppose Tory MPs had called for troops to be deployed to prevent a vote, and for Scots to be Anglicised. Scottish voters would have felt, with justice, that they were being treated as conquered vassals and the United Kingdom would have cracked apart.

Incredibly, Spanish conservatives are taking this line on Catalonia. For many on the Spanish Right, hostility to separatism is the core of their beliefs. They justify their inflexibility by pointing to the letter of the constitution, which forbids such plebiscites, but their motive is more atavistic than legalistic.

Paradoxically, they are creating the very thing they purport to oppose. You persuade people to stay by making clear they are free to leave. Three months ago, I met Raül Romeva i Rueda, whom the Catalans call their foreign minister, in his exquisite headquarters in Barcelona. I remarked that, since I was enjoying his company, I had no urge to walk out. But the moment I saw somebody trying to lock me in, I’d rush for the door. A few days later, the Spanish courts declared his position illegal.