You would not have given the address a second glance. Part of a shabby property, in a nondescript terrace, on one of thousands of identical streets built over a century ago to house North London’s commuting classes.

But the very ordinariness of the flat at Number 39 in Finsbury Park makes what happened there – until a police raid in December 2022 – even more strange and unsettling.

The occupier was Marius Theodor Gustavson and there is nothing nondescript about him; he is a large, bald, ginger-bearded, one-legged Norwegian.

Company records show Gustavson, 46, owned a number of TV motion and video production companies.

Neighbours noticed that he’d put up a large black tent in his garden. Ambulances were also often seen outside Number 39, though nothing much was thought of that at first. After all, Gustavson had an obvious physical disability and wore a metal prosthetic leg.

What they didn’t know was for years, Gustavson styled himself the ‘Eunuch Maker’. And that is exactly what, last May at the Old Bailey in London, he was found to have been doing behind the closed doors and drawn curtains of his basement flat.

Gustavson had been carrying out full genital amputations or castrations of dozens of willing and like-minded men, and posting film footage of the ‘procedures’ onto the internet. He made almost £300,000 through his open website ‘eunuchmaker.com’, which charged subscribers £100 a year and amassed 22,841 users as it became increasingly professional.

‘Arch-manipulator’ Gustavson had his own penis cut off, the tip of his nipple removed, and his leg frozen so that it had to be amputated, and recruited like-minded individuals to assist him, the court heard.

Marius Theodor Gustavson made almost £300,000 through his open website ‘eunuchmaker.com’, which charged subscribers £100 a year and amassed 22,841 users

Gustavson, who claimed £18,500 in disability benefits after losing his leg and now uses a wheelchair, appeared in court for sentencing last year by video-link from HMP Wandsworth. The judge described him as the ‘arch manipulator’ of vulnerable victims and was said to have been involved in at least 29 procedures, which were ‘little short of human butchery’. He was jailed for life with a minimum custodial sentence of 22 years.

And yesterday, the case took a disturbing new twist when a Church of England vicar admitted possessing indecent videos and images of a child being tortured by a ‘eunuch maker’ group.

Geoffrey Baulcomb, 79, was arrested after police discovered that he was in extensive phone contact with Marius Gustavson. Baulcomb, who was expelled from the Church of England last year by a disciplinary panel, was still ordained at the time of the offences and admitted to possessing ‘images which portrayed in an explicit and realistic way an act which resulted or was likely to result in serious injury to a person’s anus, breasts or genitals and which were grossly offensive, disgusting or otherwise of an obscene character’.

This extraordinary story does not make for easy reading. It concerns the far reaches of sexual identity and expression that many will find inexplicable and deeply disturbing, if not repellent. It also revives a long-standing civil liberties debate about where the line is drawn between the criminal and the consensual.

Both Gustavson and Baulcomb were part of what is called the ‘Nullo’ cult or movement. Nullo is short for gender nullification. In other words, the removal of any indication of gender.

‘Nullos’ – those who have undergone the procedure – have had their external genitalia (penis, testicles and sometimes even nipples) removed.

The case took a disturbing new twist when a Church of England vicar admitted possessing indecent videos and images of a child being tortured by a ‘eunuch maker’ group

While the procedure is mostly sought by men, women have been known to undergo clitorectomies and have their vaginas stitched closed.

Often the subjects are driven by a desire not to identify as either male or female. Others have described themselves as submissive gay men.

After such ‘extreme body modification’ as it is also known, they may identify themselves as eunuchs or ‘smoothies’.

And while, in some countries, qualified surgeons appear to offer these procedures, what was happening at Number 39 would seem to be an entirely backstreet affair.

In one interview he gave online, Gustavson reportedly said he was a Nullo himself and had carried out the procedure ‘in a very professional way’ on 58 other men. One was Jacob Crimi-Appleby, a then 17-year-old who was later manipulated into helping amputate Gustavson’s leg after ‘falling down an internet rabbit hole’ while looking up gender dysphoria online.

Gustavson also had his own genitals removed so that he would ‘look like a Ken doll [Barbie’s male counterpart] with nothing down there’.

Gustavson had been carrying out full genital amputations or castrations of dozens of willing and like-minded men, and posting film footage of the ‘procedures’ onto the internet

Gustavson kept the removed genitalia in his freezer or stored them in alcohol inside his flat

The Nullo movement first achieved global notoriety in 2012 when Mao Sugiyama, a then 22-year-old performance artist, illustrator and activist from Tokyo had his genitalia surgically removed.

In a post on X after the operation he offered to cook the amputated body parts for guests for 100,000 yen (£800), claiming he was was doing it to raise ‘awareness’.

But macabre does not begin to describe the subsequent event attended by 70 people, including a 30-year-old couple, a 22-year-old woman, a 32-year old man and a 29-year-old event planner. Sugiyama made all guests sign a waiver so he would not be held responsible if they subsequently became ill.

While cannibalism is not illegal in Japan, three organisers were charged with indecent exposure which can carry a two year jail sentence or heavy fine.

But Sugiyama argued guests knew what the event involved and the charges were quietly dropped in February 2013.

Gustavson and Baulcomb were part of what is called the ‘Nullo’ cult or movement. Nullo is short for gender nullification. In other words, the removal of any indication of gender

The knife used to remove Gutavson's penis

However, ‘gender nullification’ procedures are available in a small number of recognised surgical clinics internationally.

One such is in Palo Alto, California. The website of Dr Peter Davis says that he ‘is one of just a handful of North American surgeons who have been performing gender confirmation [also known as gender affirmation] surgeries for more than 20 years.

For his gender non-conforming patients, Dr Davis also performs gender nullification, also known as ‘male to eunuch or “smoothie” procedures.’

The procedure, it says, ‘includes a complete penectomy, orchiectomy, a reduction of the scrotal sac, and shortening of the urethra. The goal is to leave the area as a smooth unbroken transition from the abdomen to the groin.’

The case of Gustavson and Baulcomb has been both controversial and deeply disturbing, raising troubling questions. Among them: no matter how dangerous or revolting the act, should consenting adults be prosecuted for what they do in private?

This time, the Old Bailey clearly thought so. And it all harks back to a historic case that went all the way to the European Court of Human Rights.

Operation Spanner was an investigation led by the Met’s Obscene Publications Squad into male sadomasochism. The three year inquiry had begun with the discovery of a home-made video tape shot in a small town in Lancashire that showed men engaged in private, consensual, sadomasochistic sex. Some of the acts carried out with hammer and nails and scalpels were extremely disturbing. But consensual nevertheless.

The Director of Public Prosecutions decided that sixteen men should be prosecuted for offences ranging from assault to unlawful wounding. They included a United Nations lawyer and a lay preacher.

The trial at the Old Bailey took place in October 1990. Judge James Rant heard legal arguments from some of the accused that they could not be guilty because everyone involved had consented.

Judge Rant ruled that consent was not a defence and ‘people must sometimes be protected from themselves’.

At this the defendants changed their pleas to guilty. Handing down prison sentences to eight of the men of between one and four and a half years, the Judge said: ‘Much has been said about individual liberty and the rights people have to do what they want with their own bodies, but the courts must draw the line between what is acceptable in a civilised society and what is not. In this case, the practices clearly lie on the wrong side of that line.’

Five of the defendants appealed. The convictions were upheld at the Court of Appeal but the prison sentences were greatly reduced in acknowledgement that the men did not appreciate that their behaviour was criminal.

The five then took their case to the House of Lords where again they lost, as did three of them in the European Court of Human Rights.

Nine judges upheld that the laws under which the men were convicted were ‘necessary in a democratic society for the protection of health’.

Whatever the legal nuances, Gustavson’s is not a case for the squeamish, opening doors to a world of which many might wish they’d remained blissfully ignorant.