This same Green Belt legislation was also partly responsible for the abandonment of the pre-war Edgware to Bushey Heath extension as part of the Northern Heights programme of the Northern line underground railway. The Metropolitan Green Belt put great restrictions on new development, and the plan was to use the new railway to stimulate new housing around the new route; without the new housing the route was deemed no longer viable. However, as work was advanced at the onset of war, the depot was completed for use as bomber manufacture, and following the Second World War and Green Belt coming into force, it was converted into the Aldenham bus depot (of Cliff Richard's "Summer Holiday" fame), which it remained until 1985, when it became derelict. It was redeveloped in 1996 and is now the Centennial Park Industrial Estate (). Bushey Heath station would have been located at the intersection of Elstree Road and Northwestern Avenue (). Conceptual plans existed in the 1903 Act of Parliament for an Edgware to Watford railway that would have seen the railway extended at a later date though Bushey village and on to Watford market, but even less came of that than the partially completed Edgware to Bushey Heath stretch.