When BA took over Dan Air it was able to add Dan Air's flights between Gatwick and Madrid to its own as well as acquiring, instantly, the rest of a sizable operation out of LGW. I wouldn't be surprised, however, if BA's LGW-MAD operation is today as small as Dan Air's was at that time. (I know that with easyJet, Air Comet and now Ryanair on the route it's a different world.)