"The captain elected to continue the flight to its destination because he had good weather reports for Bristol and feared that divergence from the planned route with no communication might precipitate interception by military aircraft with potentially serious consequences because, with curtailed aircraft capabilities, he might not be able to comply with intercept signals."(my bold)
Notwithstanding the procedure that says you continue as flight planned, which it seems this Easy Jet pilot followed, I suspect that the Easy Jet captain either doesn't understand intercept procedures, or was making up a poor excuse (though why he felt he needed to justify his actions if he was following laid down procedures escapes me).
Electrical failure, even total, would not prevent a pilot from being able to carry out instructions received from intercept aircraft...