The mayor of London has announced plans to transform a tunnelling site into a new neighbourhood with 1,500 homes.
Sadiq Khan said Transport for London (TfL) was seeking to develop the 12.3-acre Limmo Peninsula in Newham, east London.
The site is currently being used to build the new Elizabeth Line, which is due to open in December.
Six hundred of the 1,500 planned homes will be "genuinely affordable", the mayor said.
"The Limmo Peninsula has the capacity to be transformed into a booming new east London neighbourhood," Mr Khan said.
"It is part of my strategy to free up public land and to use it to build homes that our great city so desperately needs.
"It is no secret that it will take many years to fix London's housing crisis, and we ultimately need government support - but schemes such as this prove that we can make a real difference now by delivering high-quality neighbourhoods with a large proportion of genuinely affordable homes."
The mayor is in the process of trying to find a partner to develop the Limmo Peninsula, which is TfL's largest land site.
Melanie Leech, chief executive, British Property Federation, said: "Unlocking new sites for housing is vital in meeting London's desperate need for more homes.
"In London, working with TfL and capitalising on sites such as this to add to housing supply is critical, particularly when the mayor has an ambitious target of 65,000 new homes each year."