A £4.5bn ($6.7bn) master plan for the Brent Cross and Cricklewood project is hanging in the balance, following an order by a government official to prevent work from going ahead.
The project designed by Allies & Morrison had only just received approval from the Mayor of London and local planning authority, Barnet Council.
But Communities and Local Government Secretary John Denham said there have been strong views expressed about the complex and controversial 20-year project. He is now considering a possible public inquiry.
The project will see a new town centre built, which will include 7,550 homes, a railway and bus station, shops, offices, health facilities and schools in Brent Cross, North London.