Demographics.

The term "Britannian" when used as an ethnic descriptor, seems only to refer to Citizens with ancestry in the British Isles, and so are of Celtic or Anglo-Germanic descent. However, the territorial acquisitions of Britannia suggest that large numbers of other Europeans, Hispanics, Polynesians, Amerindians and Black Africans may also live under Britannian rule, all of whom may become Honorary Britannians.

Since all conquered areas are given a numeric designation, conquered people are similarly referred to by that number, hence Japan is referred to as Area 11 and the Japanese as "Elevens". It is assumed that there are at least 18 different numbered Areas, though only a few are specified in the show. Britannians use the term "Numbers" as shorthand for any non-Britannian living under their rule.