Expand both, Runway 3 for LHR, Runway 2 for LGW.
Both are commercial enterprises, privately run and all future projects and construction should be privately funded. Government choosing one private company over another, involving public money is disgraceful. Approve both and allow them to fight it out!
Best man wins/loses.
Or, far more likely, neither get approved.
Still, if the City of London loses passporting rights post Brexit we are probably all screwed anyway.
Well you can consider us screwed then, don't be holding out for that!