Regularly see one from the RAF, As far as I am aware its a phone stalker based in Northolt.
I remember staring directly up at the crash gate and watching it circle for a good hour or so.
You can always hear it (and regularly see it on decent days) Stops in the airport to refuel on occasion.
https://www.flickr.com/photos/hertsm...es/5456663715/
https://www.flickr.com/photos/bob-holland/8080494758/
https://www.flickr.com/photos/twairc...os/8090907946/
https://www.flickr.com/photos/twairc...os/7190005154/
Really cool plane, Love how noisy it is.