A British neo-Nazi Satanist group should be outlawed by the government as a terrorist organisation, according to a report from anti-racism campaigners.
Hope Not Hate has used its annual State of Hate report to call for the Order of Nine Angles (ONA) to be banned.
The Home Office said the list of proscribed terrorist groups was kept "under review."
One of them - Sonnenkrieg Division - was influenced by the ONA's Nazi-Satanist ideology, a supernatural worldview that encourages the disruption of society through violence, criminality and sexual offending.
In the past year four teenagers linked to the ideology have been jailed in the UK for terror offences, with one of them convicted of preparing for a terror attack by - among other things - trying to alter himself in line with instructions set out in ONA texts.
In court, prosecutors described the organisation as "self-consciously, explicitly malevolent" and the "most prominent and recognisable link between Satanism and the extreme right."
Hope not Hate's report says the occult organisation - thought to have been founded in the 1970s - has become increasingly prominent online, noting that its "terminology and trappings have taken on lives of their own, adopted into the lexicon of the wider terroristic far-right."
The anti-racist campaign group, which investigates violent extremism, argues that the group's "sick ideas have drawn in young extremists in the UK and elsewhere, and have helped nourish a dangerous culture of unprecedented depravity amongst the extreme right, which has none of the moral constraints that previous generations of far-right activists had."
Yvette Cooper MP, chair of the home affairs select committee, said the home secretary "should immediately" refer the ONA to the government's proscription review group.
"The combination of Nazi-Satanism, extreme violence and sexual abuse makes it particularly troubling and action needs to be taken to prevent them grooming and radicalising other people," she said.
A Home Office spokesperson said action was being taken to "root out and dismantle the groups that promote extreme right-wing views and we are giving police the tools and resources they need to tackle this threat."
The spokesperson added: "We keep the list of proscribed organisations under review."
Counter-terrorism police have previously spoken about the increasing amount of work relating to "niche ideologies" such as violent Satanism.