A self-styled "eunuch maker" who mutilated paying customers and streamed it online has been jailed for life with a minimum term of 22 years.
Marius Gustavson admitted offences including five counts of causing grievous bodily harm with intent.
He was described at a three-day sentencing at the Old Bailey as "a lunatic", "an arch-manipulator" and "a butcher".
The Norwegian, 46, ran a lucrative business in extreme body modifications.
Warning: Contains graphic descriptions
Judge Mark Lucraft KC said Gustavson had been the mastermind of the "gruesome and grisly", "large-scale" and "extremely dangerous" enterprise.
"On one occasion Gustavson cooked what appeared to be human testicles which were then plated to be eaten, and kept other body parts as 'trophies'," he said.
Judge Lucraft told the court he was "entirely satisfied" that the motivation "was a mix of sexual gratification as well as financial reward".
Some of what happened was "little short of human butchery", he said.
'Body integrity dysphoria'
The court heard how the defendant's "Eunuchmaker" pay-per-view website advertised services including castration, penis removal and the freezing of limbs.
The Old Bailey was also told how Gustavson got others to perform procedures on him, including having a nipple and his penis removed and a leg frozen.
The website showed the defendant and his medically unqualified accomplices - six of whom were sentenced alongside him - performing a series of operations in London flats and hotel rooms on apparently willing volunteers. Some were as young as 16.
Sometimes it all went badly wrong. The court heard several recordings of 999 calls in which Gustavson calmly lied to the operator about how his victims had in fact injured themselves.
In January, three men were sentenced after admitting causing grievous bodily harm to Gustavson.
In his defence, Gustavson's legal team claimed he only wanted to "put a smile on people's faces" by offering a service to those suffering, like him, from what was described as body integrity dysphoria (BID).
However, prosecution barrister Caroline Carberry KC told the court: "We suggest that diagnosis - if it exists - may explain why it is Mr Gustavson acted as he did to have his own body maimed and mutilated, but does not explain why he made a lucrative business out of mutilating others."
Gustavson earned almost £300,000 from his website, having amassed 22,841 visitors from across the globe who paid to view the gruesome footage, the court heard.
Subscribers who paid the yearly £100 subscription would be entitled to VIP status, while victims were promised money from the video revenue.
Court documents also showed Gustavson used his business to sell human tissue gathered from the procedures, with references to a "buy it now" button.
In the end it was the bravery of one of Gustavson's victims, who cannot be named for legal reasons, that led to the website being taken down.
In 2020, the participant told Devon & Cornwall Police about the procedures carried out on him, and provided a USB stick that contained 5,000 WhatsApp messages, 100 images and a number of videos.
He told police how he had been "high on drugs" when Gustavson had first cut him with a scalpel at his flat in Haringey, north London, and how he was strapped to a bed and electrocuted.
'Mesmerised'
In later procedures the man told police how he had his testicles clamped and how Gustavson had used a red-hot iron designed by the victim to brand him with the initials EM - which stood for eunuch maker.
In a victim impact statement read to the court, the man described how he had been "mesmerised" by Gustavson, but now recognised he had needed to see a psychiatrist "not a back-street surgeon".
"I realise I have trusted a wrong person and Gustavson is in fact a lunatic."
The thousands of messages handed to police revealed how Gustavson was an "arch-manipulator of victims", who may have consented to the procedures but were themselves vulnerable, the prosecution said.
Having pleaded guilty to a series of charges including conspiracy to cause grievous bodily harm with intent, making and distributing indecent images of a child and possessing extreme pornography, Gustavson did not need to give evidence at a trial.
Investigations by journalists into Gustavson's background in Norway, and from what his defence team claimed at court, make it possible to trace how the once-respectable community figure descended into a spiral of criminality.
Originally from a small town to the south-west of Oslo, Gustavson was a postal worker and the chair of an LGBT charity, known for organising Pride weekends as well as the traditional "Russ" celebrations - a series of events and parties high school students enjoy before their final exams.
But by 1999 he had received a suspended prison sentence for a fraud committed against a housing co-operative and in 2001 he was sentenced to eight months for internet fraud.
Defence barrister Rashvinderjeet Panesar said Gustavson's marriage in 2005 kept him "stable" but it broke down in 2016 - which was when he began to "modify" himself.
Gustavson moved to the UK in 2012 and was living in London in 2017 when he had his penis removed by one of his co-defendants, Damien Byrnes.
Two years later he arranged to have part of his leg frozen and a nipple removed.
'Barbaric'
The procedures led to "feelings of empowerment and greater acceptance of himself and feelings of contentment with his own body", Mr Panesar said.
"From there the Eunuchmaker website began. He does say he wished to put a smile on other people's faces - he wanted to help.
"He was stuck in a body he wanted to make changes to, and understood there were more people out there who wished to do the same."
By the time of his arrest his involvement had become an "addiction" and he could no longer stop himself being present at the procedures and making videos, the barrister said.
Six men, who all admitted conspiracy to commit GBH with intent, were sentenced alongside Gustavson:
- Ion Ciucur, from Gretna Green, was sentenced to 5 years and 8 months
- Peter Wates, from Croydon, south London, was sentenced to 12 years
- Janus Atkin, from Newport, Gwent, was also sentenced to 12 years
- David Carruthers, also from Newport, was sentenced to 11 years
- Ashley Williams, also from Newport, was sentenced to 4 years and 6 months
- Stefan Scharf, of no fixed address, was also sentenced to 4 years and 6 months
Gustavson never expressed any feelings of remorse for the crimes he committed or for the lifelong physical and psychological harm done to his victims.
Thursday's sentence showed the court's view that he is a very dangerous individual.
Kate Mulholland from the Crown Prosecution Service said: "Marius Gustavson ignored the risks of performing unnecessary surgery on vulnerable men, for sexual gratification and financial gain.
"He actively recruited participants through his website and was paid to stream the footage of these barbaric procedures.
"Performing extreme body modifications is against the law and the CPS won't hesitate to prosecute these horrendous crimes."