Sixteen London Underground stations have just been listed on the advice of English Heritage - the BBC have some good vintage photographs. (One idiosyncracy of the list is that Oxford Circus appears twice: although we think of it as a single station, it has two buildings.) These not the first on the network to be listed: there are 72 in total on English Heritage's National Heritage List.
The full list of protected underground stations now includes Acton Town, Aldwych, Arnos Grove, Baker Street, Balham, Barking, Barkingside, Baron's Court, Belsize Park, Boston Manor, Bounds Green, Bow Road, Brent Cross, Caledonian Road, Chalk Farm, Chesham, Chiswick Park, Clapham Common, Clapham South, Cockfosters, Colliers Wood, Covent Garden, Ealing Common, Earls Court, East Finchley, East Ham, Eastcote, Farringdon, Fulham Broadway, Gloucester Road, Great Portland Street, Harrow & Wealdstone, Hendon, Holloway Road, Hounslow West, Kennington, Kew Gardens, Kilburn, Loughton, Maida Vale, Moorgate, Mornington Crescent, Notting Hill Gate, North Ealing, Northfields, Oakwood, Oxford Circus (twice), Paddington (District & Circle), Park Royal, Perivale, Piccadilly Circus, Rayner's Lane, Redbridge, Ruislip, Russell Square, South Kensington, South Wimbledon, Southgate, St James's Park, St John's Wood, Sudbury Hill, Sudbury Town, Tooting Bec, Tooting Broadway, Turnpike Lane, Uxbridge, Wapping, West Acton, West Brompton, Willesden Green and Wood Green.