In message , John Rowland
writes

Really, of course, we shouldn't. The first gap should be after the bit
that you don't have to dial if it matches your own phone number, i.e.
020.
All very interesting, but just goes to show the snobbery of the people
who try to point out their living in the London area, as I've never read
anything authoritative on telephone number groupings.
--
Clive.