In the next two weeks designate two new town development corporations in the Oxford-MK-Cambridge Corridor.
For generations 1-2 New Towns the development corporation was designated, the border defined and then a masterplan drawn up within it. The problem was it led to places like Skelmersdale, where the masterplan was warped to fit within the boundary.
For the thrird gen New Towns starting with Northampton the development corporation was formed and then drew up a masterplan. The boundary being defined after the masterplan set the area. There is nothing in the New Towns Act as I can see to prevent that.