The excavation will descend over 50 feet below the surface say reports, deeper than the height of nearby houses, and will feature a 45-foot swimming pool, hot tub, sauna, massage room, ballroom, covered courtyards, staff accommodation, parking, a turning circle and car lift.
More top news
A police officer who spent six days crawling the London Marathon in a gorilla costume has finally completed the 26-mile route.
The victim of a "violent and sustained attack" on the top deck of a London bus has been named as Archie Sheppard.
Transport for London has made the badges and accompanying cards permanently available after a successful trial in autumn last year.