My mate who is a Londoner has a wife who is a Kiwi. She's been here for donkey's years, probably over 30 of them. She has a NZ passport, always uses it although she also has a UK one.
Recently, they returned to the UK from a holiday in Malta. Upon entering the UK she was challenged, and in order to validate her right to be here, was asked random questions from a "test".
The first question was "what's the population of Wales."
No, this isn't any kind of joke.