Jed was showing us how it is
No he wasn't. Bad things do happen and people go unpunished, usually because of laziness and incompetence, but no police force would have been allowed to run up a bill of thousands upon thousands for the frequent appearance of dozens of armed police and the use of the police helicopter, again, thousands per hour. Not to mention the body count.
An investigation by a team of forensic accountants would be more to the point: 'who signed off these bills?' would lead to H or more likely, 'Y'.
Then the murderous staff at the local prison, the unbelievable technology available to the prisoners, James Nesbitt as a dead red herring, the murders of Jill Dando and Stephen Lawrence to give it gravitas, and the borrowing of a mis- spelling as a clue: Morse did it so much better in an early episode, involving the use, or misuse, of z or s in realize.
A sloppy episode and a poor conclusion, with no clues given: it could have been anyone.
To round off my diatribe: the lecture about integrity had about as much impact as those issued by Prince Harry.