Just to clear up a small misunderstanding...
It's clear from several comments here that people don't realise that WC was never a bobby on the beat. References are made to his possible interactions with the public and having colleagues at the station which are misleading people to believe that he was a regular bobby who attended parade with daily colleagues and sat in the canteen indulging in sexist banter etc.
This is entirely wrong.
He joined the police later in life than most and was never a "bobby on the beat" type of uniformed policeman that people think of when they hear he was a police officer. He has only ever worked in specialised units and when he committed this horrific crime was in a bodyguard type of role for politicians and diplomats - hence he could be required to carry a gun.
Lastly, people are assuming that his copper mates at the station and in the canteen jokingly called him 'the rapist'. This never happened. He didn't work at a police station, for starters, but also it was his mates at his previous workplace, a garage, who gave him that nickname because female customers seemed uncomfortable in his presence. The police were unaware of this nickname. It only came out after his name was published and his former workmates recognised his name and face in the papers.
None of this changes much but I do think it's important to get the facts right.
Some people are trying to paint a false picture of a police station where everyone knew he was a potential rapist and joked about it, when in fact his superiors should have sacked him for it. This is wholly incorrect.
I don't see how the Met can be held responsible for the completely unpredictable, unforeseeable freak actions of this man. Especially considering that his wife saw him up close every single day, had known him intimately for years, chose to marry and have more than one child with him, and was still living with him when he committed the murder ---- and even she had no idea, no clue, that he would ever do such a thing.
And BTW she must be going through absolute hell right now.
Ditto his parents, siblings, friends and neighbours, who must all be horrified that someone they thought was a normal guy turned out to be this psychopathic murderer. They are all probably torturing themselves daily with questions like "why didn't I notice something?" and running over everything he ever said and did to try to find some clue in retrospect of what he was capable of.