A shocking new Netflix documentary retells the horrific crimes of twisted serial killer Dennis Nilsen – who counted a young High Wycombe man among his victims.

Muswell Hill Murderer Nilsen died behind bars in 2018, at the age of 72, having carried out a savage killing spree during the late 1970s and early 1980s.

He is believed to have killed as many as 15 people, many of them homeless young gay men, after luring them into his north London home.

One of his victims was High Wycombe’s John Howlett, who was 23 at the time.

He was the first of Nilsen’s victims to be murdered at 23 Cranley Gardens – the Muswell Hill attic flat he moved to after his landlord decided to renovate 195 Melrose Avenue, the home he had already murdered a number of young men.

John – who was nicknamed John The Guardsman by Nilsen because his woolly hat looked like one belonging to a guardsman – was brutally strangled as he slept at Cranley Gardens in March 1982.

He had apparently woken up during the horrifying ordeal and was later drowned in a bathtub.

The documentary discusses how 'John the Guardsman' was known in London as a 'rent boy' - a young male prostitute.

Police were able to identity 'John the Guardsman' as John Howlett. When they spoke to his mother, they found John had left home "of his own accord", got involved in drugs and "there was quite simply an acceptance that her son had died".

Nilsen was jailed for life in 1983, with a recommendation that he serve a minimum of 25 years, for six counts of murder and two of attempted murder.

Nilsen died in 2018 behind bars at the age of 72.

A new Netflix film about the mass murderer aims to shine a light on how the callous killer got away with his crimes for so long.

Memories Of A Murderer: The Nilsen Tapes was released on August 18 and used more than 250 hours of never-before-published cassette tapes of the killer’s private recordings from inside his prison cell and 7,000 pages of his unedited autobiography.

Director Michael Hart said: “The idea in our mind at the time was that we’ve got all this archive, surely there’s a documentary that we can put together and maybe ask the question, why did he do what he did? Is this a way into his mind? A serial killer’s mind.

“However, I spent seven or eight weeks listening to the audio, and it was a tough, tough process, it was probably made even harder because of the pandemic because I just didn’t have all my usual things to do to take a break from work, so it became quite intense.

“But what I realised was by the end of the eight weeks, when I had gone through all the tapes, was I feel and believe that we have here is more of a documentary, not about why Dennis Nilsen did what he did…but why did he get away with it. And how did he get away with it for as long as he did?

“This happened over four or five years and then there were attacks before that. So that was the question.”

Describing the act of sifting through the material, Harte said: “The more you dig into his story, the less you start to understand about him because he’s so contradictory.

“And what I realised is when I was listening to his audio tapes was if we’re going make this film, we obviously have to interview other people here... and what I realised was that a lot of the things he was saying, more often than not, were being contradicted by other people, by the people I interviewed.

“So what I actually had on my hands more than anything was, here’s an unreliable narrator.

“But what I can try to understand is the fact that I could learn much more about why he got away with what he did. The second half the film is structured in such a way that that question starts to grow, why did he get away with so long

“For me, that is (because of) prejudice. It seems that he understood prejudice himself, in terms of his background, not just in the police, but just the bigger picture in society.

“Prejudice really allowed it to happen again, and again, and again. People had tried to warn others that they’d been attacked, and they weren’t listened to, for various reasons.”