It [a British hub] requires space for two runways to be able to carry out independent simultaneous instrument approaches in order to be able to maintain arrival rates in poor visibility (that will rule out places like BHX).
Although I dislike the place, the only common sense option that could be available soonest is LHR. It needs that extra runway very, very soon in order to be able to maintain arrival rates and avoid cancellations whenever it is foggy.
I'm confused. Does a hub need two runways or three ?