Same issue for the hundreds of thousands of foreigners on visa or residence permit here. A residence permit issued by a Schengen country also serves as a Schengen visa.
I have a perminent residence visa for Germany and have flown to and from the UK a number of times with no problem, twice on airlines, once GA. Or maybe I just didn't get caught?
P.S. and on one of those trips I had the priviledge of meeting our own Mad_Jock personally!
(plus a few other former Ppruners....)