In message , at 11:50:51 on Tue, 2 Sep
2014, Someone Somewhere remarked:
I haven't looked at the schedules but I can well believe every London
airport has several flights a day to particular european destinations
that could easily be consolidated into less "movements" in larger, more
efficient, planes if that were the case.

Heathrow/Gatwick don't have flights to very many European destinations.
That market is dominated by low-cost airlines from other airports.
--
Roland Perry