Hilton Park Lane - 22m2
The Dorchester - 26m2
The Cavendish - 20m2
It's not really fair to compare Park Lane hotels to ones situated in other areas of London, and to ones which are in a different category; for example Covent Garden is far removed from Mayfair/Belgravia.
I understand what you're saying with regard to hotels not stating the room size on the description, however it is to be expected when booking in certain areas.
I don't think it is to be expected at all.
Or why my experience of hotels in lower categories should be of larger rooms. The Covent Garden Travelodge is only a stones throw from the Waldorf/Savoy and the Marble Arch Thistle is a short (5 minute) walk from Mayfair/Belgravia.
Doesn't make any sense to me why lower priced 2/3 star hotels located so near their 4/5 star counterparts should have much bigger rooms.
I'm genuinely really curious to know which hotels really are giving their punters such tiny rooms. I've never spent enough on London accommodation to know anything but decently sized ones.