Regrettably it was/is only a matter of time.
BA (mainline) talked about pulling out of JER a while ago, but gave in to the opposition, including a lot of heavyweight banks.
GCI was always going to suffer once Brymon etc. vanished, and as for LGW-GCI, that made money with an ATR72 and CFE costings, but there's no way it would ever work with BA costs on a larger aircraft.
Leave the Channel Islands to BE/FlyBE. They've got the right aircraft and costs for the CI routes.
(And the CI is a perfect niche market for FlyBE in it's new 'lower cost' mode, cos they won't be able to compete head-on on core routes with the proper low-cost carriers!)