This is the main reason why RAF Wittering is still around …..
Wittering is a ‘well found centre of specialism’ as a ‘support enabler’ to the RAF and Defence objectives, that’s why it still exists and presumably will continue to do so ……. Either that, or due to potential military ground contamination, land value (or lack of land value), potential/lack of potential for housing/commerical development and the very important thing that ruins plans to dispose is as you have pointed out the terms under which sites went to government.
Under BDES, which I have thumbed through in hard copy and electronic copy many times …..
https://assets.publishing.service.gov.uk/media/5f6344b18fa8f5106b23aa86/Better_Defence_Estate_Dec16_Amends_Web.pdf
….. Defence have two key targets to dispose of 30% of the estate and in doing so to facilitate the enabling of land release for housing development of 55,000 new homes.
They go hand in hand, except that sites no longer required for modern defence needs aren’t necessarily where people will want to live - especially if the site that would be closed is the main employer in the area.
That’s before someone confirms whether or not government can sell the land, so the valuable land turns out to be required to be given back to the previous landowner rather than being used to facilitate the replacement site development
Or the environmental cleanup
Or the local MP complains about losses of employment
Or the planning of expanding site B to rationalise what was in site A to close down won’t pass planning because that means putting buildings onto the open green land next door to site B
Next let’s wait for someone to have the idea again of selling off the lovely Wiltshire land at Porton Down
