Police noted that Brock had tattoos of prominent Nazis from the 1930s and 1940s, along with runes and other symbols adopted by neo-Nazis and white supremacists.
A tattoo on his shoulder featured the Totenkopf skull and cross bones adopted by the Nazi SS which has since been used by the British neo-Nazi group Combat 18.
Emma Gargitter, prosecuting, said the room was “filled to the brim with an eclectic mix of items, amongst them, items demonstrating an interest in extreme right wing and white supremacist ideology”.
The room also included flyers for the National Front, with a letter to Mr Brock, addressed “Dear Patriot, Many thanks for your enquiry and interest in the National Front”.
There were books about the American white supremacist group the Ku Klux Klan (KKK), a copy of Hitler’s Mein Kampf, and another about Combat 18, while under the bed was a “certificate of recognition” from the Klan.
Among the material on his electronic devices was a photograph of Brock posing in his bedroom, wearing a balaclava, and holding a large firearm, in front of the swastika flag, the prosecutor said.
Another photograph showed Brock in front of the confederate flag, wearing a cap with the words “Make America Great Again”, the slogan of the campaign for Donald Trump.
A short video apparently shot in Brock’s bedroom showed a Nazi flag being waved and a KKK figurine.
A video in three parts showed unedited footage filmed by Brenton Tarrant as he shot 51 people dead at two mosques in Christchurch, New Zealand, in March 2019.
Other videos included KKK cross burnings, and one of the decapitation of a blindfolded man.
His hard drive included a folder labelled “Army-Military-Manuals” which contained two manuals for an AK47 assault rifle, and others for US army pistol training, and explosives, along with a copy of a document known as the “al Qaeda manual”.
The documents were said to include three that were useful for terrorists.
Brock had images showing a number of anti-Muslim and other racist memes, Ms Gargitter said.
Among the material on his electronic devices was a video called Hail Combat 18, which featured men in balaclavas wearing sweatshirts with the words “Blood and Honour” loading and using firearms, one of whom warned: “The war is coming.
Other folders were labelled: “KKK”, “Enoch Powell”, “Knuckle Dusters”, and “Runes” and a number had names referring to “WW2” and the Nazis.
He had used his computer to search for the National Front, National Action – a proscribed right-wing terrorist group – the KKK and “racist photos”.
On a file called “tattoo ideas” he had the logo of the banned right-wing terrorist group National Action.
Interviewed by the police, Brock claimed he was “not interested in rubbish like this” and was a “World War One, World War Two, the Falklands and the Gulf” military collector.
He claimed that two men would sometimes come to play Play Station 2 games with him in his bedroom in the evenings. and one of them might have downloaded the material while he was out of the room “making a cup of tea or a sandwich”.
Brock was found guilty of three charges of possessing information useful for terrorism and will be sentenced in May