Six men jailed for their roles in an extreme body modification ring which saw its leader have his penis cut off with a kitchen knife can challenge the length of their sentences, the Court of Appeal has ruled.

Marius Gustavson, Janus Atkin, David Carruthers, Ashley Williams, Damien Byrnes and Jacob Crimi-Appleby were jailed for their involvement in the enterprise, which carried out male castration, penis removal and other “grisly” procedures on an unprecedented scale on people as young as 16.

Gustavson, who led the group, once cooked human testicles to eat in a salad and also froze his own leg so it needed to be amputated, netting more than £300,000 between 2017 and 2021 after posting videos of various procedures on his Eunuch Maker website, the Old Bailey previously heard.

Barristers for the six men – whose sentences range from four years to life with a minimum term of 22 years – have asked the Court of Appeal for the green light to challenge the length of the jail terms.

In a short hearing on Tuesday, three senior judges said an appeal against the sentences could take place.

Mr Justice Murray, sitting with Lord Justice Edis and Judge Shaun Smith KC, said that while it was “thankfully, a highly unusual case”, the appeal was “arguable”.

The Old Bailey heard earlier this year that extreme body modification is linked to a subculture where men become “nullos”, short for genital nullification, by having their penis and testicles removed.

Prosecutor Caroline Carberry KC said Gustavson, 46, was linked to at least 29 procedures and that there was “clear evidence of cannibalism”.

The court heard that the defendants used a wide variety of tools such as clamps used for animal castration, with body parts put up for auction online with a “buy it now” button.

Gustavson also offered to sell the severed penis of one of his victims for hundreds of pounds, with some 22,000 subscribers paying to access videos on the Eunuch Maker website with varying levels of membership from “free” to “VIP” which cost £100.

The Norwegian was arrested after he used a red-hot iron to brand a man’s calf with the letters EM – for Eunuch Maker – and after he was detained, police found his penis in a drawer of his home in Haringey, north London, four years after it had been amputated.

Gustavson, who attended Tuesday’s hearing via a video link, was jailed for life with a minimum term of 22 years after pleading guilty to conspiring to commit grievous bodily harm, five counts of grievous bodily harm with intent, making and distributing an indecent photograph of a child, and possession of criminal property.

The other defendants also admitted their part in the conspiracy relating to 13 victims.

Atkin, 39, Carruthers, 61, and Williams, 33, of Newport, Gwent, were jailed for 12 years, 11 years and four years, six months respectively for conspiracy to commit grievous bodily harm.

Byrnes, 37, of north London, and Crimi-Appleby, 24, of Epsom, Surrey, were jailed in January having admitted causing grievous bodily harm to Gustavson.

Byrnes was jailed for five years for removing Gustavson’s penis with a kitchen knife on video at his home on February 18 2017.

Crimi-Appleby was jailed for three years and eight months for freezing Gustavson’s leg leading to the need for it to be amputated in February 2019.

On Tuesday, Mr Justice Murray said that the three judges were “satisfied that it is at least arguable” that it was “wrong in principle” for Judge Mark Lucraft KC to use sentencing guidelines for grievous bodily harm with intent, “which are, by definition, non-consensual offences”.

He continued that it was arguable that “the judge did not give sufficient weight to the fact that almost all of the victims… appeared to have been content with the outcome of the body modifications they underwent”.

The full appeal will take place at a later date.