All these neat, even obsessive, classifications - and then people spoil the neatness by falling in love with somebody from another classifications.

I used to have a colleague who came fromm Ireland, and had met her husband when she was working in Gibraltar, where he'd been born, from a Portuguese Indian (Goan) family. Their children were entitled to passports of at least four countries. I remember her trying to work out how the family were supposed to fill in the ethnic origin question on the national census form.