A group which campaigns to preserve the best of the 20th century's architecture has called for Sir Nicholas Grimshaw's Waterloo International Terminal to be given listed status.
Sir Nicholas Grimshaw's terminal for Eurostar train services opened in 1994 and has been largely disused since 2007.
Work is now under way to convert the platforms for use by commuter train services.
"We recognise that alterations will need to be made in order to bring the terminal back into use," said Tess Pinto, Twentieth Century Society conservation adviser.
"However, these should be conservation led, as with the highly successful St Pancras restoration, where works were robustly justified and undertaken with close attention to everything that makes the original building special.
"We are calling for grade II* listing so that the alterations will take into account the undoubted significance of this world-class building."