Well, I checked my databases for legislation that defines London, or
indeed the City of Westminster as the 'Capital' and drew a blank (Im
a lawyer). As I'm sure your aware we don't actually have a written
constitution. Arnt we the lucky ones! We do have definitions of what
a city is, but not in a'legal' sense, which generally is a place with
an Anglican Cathedral, but nowadays the government can confer city
status on conurbations of an undefined size, undefined facilities,
and undefined qualities.(Typical) Recently a number of cities applied
and if my memory serves me, Brighton and possibly Wolverhampton
became cities in the eyes of the government. I do know that Luton and
Milton Keynes applied and failed.
As for legal definitions of London as a Capital City, i'll search a
little more. Its interesting the Hague is not a Capital, cos I always
thought it was. You live and learn. Michael