The ringleader of an extreme body modifications website was driven towards the subculture by a desire to be “the architect of his own body” after his marriage broke down, a court has heard.

Through his “eunuch maker” site, Marius Gustavson and other “like-minded individuals” carried out multiple mutilations, “the scale of which is without precedent”, prosecutor Caroline Carberry KC previously told the Old Bailey.

The 46-year-old Norwegian required hospital treatment after having his penis and leg removed during body modification procedures.

Rashvinderjeet Panesar, defending Gustavson, said the breakdown of his 11 year marriage in 2016 which had “kept him stable”, was a “trigger” for his extreme activities.

“When it came to an end it sent him into a spiral,” Mr Panesar said.

“He had a desire to be the architect of his own body.

“His modification led him to feelings of empowerment.

“It appears at face value to be something that’s become an addiction for him.”

The lawyer said Gustavson had been diagnosed with body identity integrity disorder, which accounted for his desire to have body parts removed.

Gustavson had not participated in any body modification before the end of his marriage, Mr Panesar said.

He now wished to return to his native Norway, where his views are more likely to be accepted, Mr Panesar added.

“Arch manipulator” Gustavson, of Haringey, north London, has previously admitted charges including conspiracy to commit grievous bodily harm.

He appeared for sentence alongside six other men who had all admitted their part in the lucrative scheme.

The charges relate to 13 victims who are being safeguarded by specialist detectives.

The wide-ranging conspiracy also involved the removal and trade of body parts, the court was told.

Ms Carberry said Peter Wates, a retired former member of the Royal Society of Chemists, had been “in the business of purchasing body parts from Gustavson”.

During a police raid on the South Wales home of David Carruthers, “testicles were found in a chest freezer”, the prosecutor said.

Alexander Greenwood, defending Carruthers, said the testicles found in his freezer were Carruthers’ own.

But for his connection with the “spider web” of Gustavson, Carruthers would “never have troubled these courts”, Mr Greenwood said.

Carruthers was also diagnosed with body identity integrity disorder and removed his own testicles, the court heard.

“He believed he was assisting those with the same condition”, his defence lawyer said.

Helping Gustavson with his body modification activities was a “terrible mistake”, Mr Greenwood added.

Andrew Taylor, defending Janus Atkin, who had been completing a veterinary course, told the court his client had “fallen under the spell” of Gustavson.

Mr Taylor said: “There are people in this country who are born into bodies they might not want.

“Mr Atkin’s primary purpose was to help others.

“This truly is an epoch-making case.”

Paul Dixon, defending Wates, said the retired chemist was an “altruistic individual who wanted to help”.

Gustavson pleaded guilty to conspiring to commit grievous bodily harm, five counts of grievous bodily harm with intent, one count of making an indecent photograph of a child, one count of distributing an indecent photograph of a child and possession of criminal property contrary to Section 329(1) of the Proceeds of Crime Act 2002.

Ion Ciucur, 30, of Gretna, Scotland, Wates, 66, of Purley, Surrey, Stefan Scharf, 61, of no fixed address, David Carruthers 61, Janus Atkin, 38, Ashley Williams, 32, all of Newport, Gwent, pleaded guilty to conspiring to commit grievous bodily harm.

The sentencing hearing continues.