The teenage leader of a neo-Nazi group has been convicted over offending that began at the age of 13, making him the youngest person in the UK known to have committed a terrorist offence. The boy, from Cornwall, who cannot be identified, appeared before the Old Bailey in London via video link on Monday and admitted 12 offences – two of dissemination of terrorist documents and 10 of possession of terrorist material. At 13 he downloaded a bombmaking manual and began gathering terrorist material. Later in the same year he joined the neo-Nazi cult Fascist Forge, and at 14 he went on to share far-right extremist ideology in online chatrooms. The court heard that the youth, now 16, led the British branch of the now banned neo-Nazi terrorist organisation Feuerkrieg Division (FKD). The group idolises mass murderers such as those who carried out far-right terrorist attacks in Norway, the US and New Zealand in recent years. FKD encourages so-called “lone wolf” attacks. Between October 2018 and July 2019, the boy collected a significant amount of far-right material and was active on online platforms, expressing racist, homophobic and antisemitic views. He talked about gassing Jewish people, hanging gay people and wanting to “shoot up their parades”, the court heard. Naomi Parsons, prosecuting, said police searched the property where the boy lived with his grandmother following reports that he was constructing a weapon. No weapon was found but officers discovered a Nazi flag and well-known Nazi slogan on the garden shed, as well as several manuals about making weapons and instructions on how to kill people on his phone and computer. “The age is the alarming factor and his conduct betrays a maturity beyond his chronological age,” Parsons said. In a police interview, the defendant said he had made racist, homophobic and antisemitic comments “to look cool”. It was claimed that he was in touch with a 14-year-old Estonian boy who founded the FKD and was responsible for vetting and recruiting members and propaganda. They used encrypted messages to discuss their hatred of particular groups. The defendant then set up FKD GB and recruited five British members from online platforms, including Paul Dunleavy, 17, from Rugby, who was jailed last year for preparing acts of terrorism. The cell wanted to enact “white jihad” and the genocide of people who were not white, the court heard. In mitigation, Deni Matthews said the defendant had a “simply dreadful childhood”, and everything he did was in order to “seek approval” from others online. The judge Mark Dennis said he would need to consider whether the teenager had been immature or naive before passing sentence. He said: “I need to assess a person of this age who sends these messages, [and] whether this is true beliefs or the product of firstly grooming but then self-aggrandisement and the other matters.” The boy was granted bail subject to strict conditions including residing at his home and attending youth offending services, along with a ban on using computers without police permission and bans on using any private browsing mode, encryption software or virtual storage devices such as the cloud. The boy will be sentenced on 8 February.