aircraft over colchester followed by two fighter jets

[DogSpew]

GMM - what you say is possible and occurs quite often, however a professional pilot would revert to 121.5 and make all possible attempts to contact someone. This happens quite often and results in a return to normal comms.
Also most responsible and professional pilots monitor 121.5 on the second VHF radio set for loss of comms and prevents the launch of fighters to intercept wayward aircraft. Maybe this aircraft has only one VHF radio??

I was flying this night and heard the repeated radio calls from London CTR on 121.5 over a 5 minute period. Obviously no-one on this aircraft was listening for whatever reason.