The most important urban development in London is currently being built with little fanfare and even less scrutiny. It will create no office space, no homes, no shops and no leisure facilities yet it will change the shape of London for years to come. Sadiq Khan has nothing to say about it. Local councillors are supposedly powerless to stop it. Londoners haven’t been asked if they want it and even on a clear day it’s quite hard to tell exactly what it is.