No you don't live in the real world, you live in the world fluffy people are trying to create where everything is wonderful and the worlds nasty people all live in la la land. To be honest I don't see many politicians doing that either, until of course they are properly briefed. I'm guessing, being on a military aviation forum, you either know something, about the intricacies of getting into London, be it piloting, or air trafficking it? Then you would know, your namesake just isn't an option, nor never will be and LCA rules preclude just about everything with the exception of what they have now bouncing off those rules daily.
The precision radar head at Northolt I'm sure remains fundamental in the first rule of government and I am certainly not living in your " flying in thousands of non existent troops in case of civil unrest... Is fantasy.......... Fantasy. But I do live in the real world where sometime nasty things happen sadly more often than you'd think and not necessarily in London.
Not that I give two figs anymore about military airfields, but I'd also like to comment on your "slam dunk TBH" theory, surely if the south east needs more houses? Why not build them in the south east, not north west London! Can I suggest if Mr Whateverhescalled (London Mayor) is hell bent on an airfield, maybe Biggin Hill? I seem to remember that was south east it was only useful as a turning point to avoid another London rule.