The point was; not only was there loss of coms, they also were not on track, having made an unforeseen turn near Newcastle.
In this case the only way to verify all was still OK was to force the CRJ to land at an airfield of our choice. Once on the ground, the Police will verify by physically going on-board.
Some here appear a little naive after 9/11. These fighter aircraft are fully armed for a reason. The unfortunate and ultimate result could possibly lead to a shoot down if the aircraft had been hijacked and failed to comply with the interception.