On Sat, 24 Nov 2007 01:09:34 +0000, Tom Anderson wrote:

All "Underground" stations have surface buildings which are above sea
level, AFAIK.

Regent's Park and Notting Hill Gate have no surface buildings.

Hyde Park Corner too, isn't it?

Yes, there are several.

(Off the top of my head:
Tottenham Court Road
Old Street
Piccadilly Circus, unless you count Trocadero

I can't mentally place surface buildings at Mansion House or Bank
either, but I'm not too sure about those.)