ZRH has a slick deicing operation, whereby the aircraft are treated at the hold, thus avoiding holdover problems.
They have multiple rigs and do 2/3 aircraft in parallel. AFAIK the airport operator does the deicing, whereas BAA at LHR does not and the airlines are responsible.
Of course, you need to make an investment in equipment to achieve efficient deicing.
I can only hope that BA get their fingers burned enough time with EC compensation (hard to claim weather driven cancelations, if other carriers are operating.) I currently have a summons against BA for such an instance, with lawyers on the case.
Of course, when the conditions are really bad and the airport is closed, everyone is grounded, at LHR, ZRH or elsewhere, but it is the speed of recovery that counts and you need the right kit and trained operators to achieve that.
UK air traffic has been paralyzed for two years in a row now, that cost benefit analysis must be skewing.