I have left out a number of airports that has only PSO routes or airports that are vital links to remote communities like Land's End St. Just, Inverness and Kirkwall.
LN-KGL
INV has more than just PSO routes
LTN,BRS, LGW( both EZY and BE) BHX,MAN,AMS,ZRH
And INV is not a remote community just because it is a long way north of the Watford gap