The Grade II-listed Elliott School in Putney, whose former students include members of Fleetwood Mac, The xx, So Solid Crew, The Maccabees and actors Pierce Brosnan and Alun Armstrong, now faces losing buildings, playing fields and an outdoor stage.

Wandsworth council launched a consultation about selling off assets and doubling pupil numbers to 1,200 after the school lost out on a £40  million rebuilding grant.

The consultation period doesn’t end until next week, but plans are on an estate agent’s website now.

Former student Ed Lattimore, 31, who is leading a campaign to save the school, said: “There is a large commercial pressure pushing the sale forward before the public consultation has ended.”

A council spokesman said it was “soft marketing” the site in order to find out how much it was worth.