What precedent does this set for bypassing normal planning rules?

An excellent one we hope! Before we nationalised planning in 1947, developers would be compensated by local authorities if their plans were refused. We reversed that in a climate where it was expected that local authorities would do all the building. Otherwise some of our greatest projects, The Olympics, the Channel Tunnel, Canary Wharf, and Milton Keynes, have used primary legislation and development corporations to push through major building projects of national importance.