A Sakian question

I am translating Saki, and I wonder and ask everyone: why does he say 'the City, where the patriotism comes from' in the following context: "The Beauwhistles weren’t born in the Purple, you know, but
they’re getting there on the instalment system--so much down, and the
rest when you feel like it. They have kind hearts, and they never forget
birthdays. I forget what he was, something in the City, where the
patriotism comes from; and she--oh, well, her frocks are built in Paris,
but she wears them with a strong English accent" (Reginald on worries). Notice that I am not an Englishman, and even less an Edwardian Englishman.