I forgot to comment at the time on the passing of former Detective Sergeant Challenor of the Met. who slipped off the hook three weeks ago. The Challenor case was a big deal back in the sixties; that and the Sheffield Rhino Whips case - heady days!
Challenor had a proud career in the CID, blithely fitting up anyone he didn't like. He was, for some reason, particularly vindictive towards people with disabilities and people of a Mediterranean appearance. Possibly this was connected to his wartime experience in Italy as a POW.
Challenor slipped up when, at a political demonstration, he nicked one Donald Rooum, a peace activist, along with some others. He charged them with possession of offensive weapons, to wit, carrying bricks about their persons. Rooum refused to roll over, did not cooperate, i.e., avoided all contact with the magically manifested brick, and so was able eventually to prove his innocence. In the course of doing so he exposed Challenor as a bent copper, more than that, a nutter out of control.
None of which fazed the judge, who found Rooum not guilty but refused his application for damages. He also found some other poor joker guilty on the same discredited evidence from the same discredited copper. The Met. of course was not interested in delving into Challenor's murky past; too much perversion of the course of justice, too many compromised coppers.
But the genie was out of the bottle and some sort of action had to be taken. Challenor was declared to be a bad boy, but a nut case (true), therefore unfit to stand trial for his many crimes. He was committed to a mental institution, and after a few weeks, quietly released, later to obtain a job in the legal system (no kidding!). We may assume that he received a full pension for his contribution to the maintenance of law and order. After all he was never found guilty of any offence.

Addendum: after writing the above I took a look at wikipedia to see if there was anything on the Challenor case there. I found the linked article. Reading it I learn that I was too dismissive of the Metropolitan Force's response to the affair. Though Challenor got away with his crimes three other tecs were jailed.
I also learn that "doing a Challenor" became police parlance for retiring on grounds of illness to avoid investigation. If memory serves there was a lot of that about at the time of Operation Countryman and during the Stephen Lawrence investigation.
Wikipedia also has an article on Donald Rooum.