Alex Davies, 27, set up National Action nine years ago and continued to associate with its members after the group was banned by the Government in 2016.
On Tuesday, Davies was jailed at the Old Bailey for eight-and-a-half years by Judge Mark Dennis QC.
The judge also ordered him to spend a further year on extended licence.
Judge Dennis said: “I’m satisfied the defendant played an active and prominent role in concert with his trusted associates in trying to disguise the continued existence of the organisation in defiance of the ban.”
Winchester Crown Court was told last month that Davies, from Swansea, went on to set up an offshoot organisation to circumvent the Home Office ban.
The conviction of Davies is the last in a raft of 19 prosecutions of those who continued their membership of the group after it was outlawed.
Alex Davies
Andrew Matthews
During a four-week trial, the jury heard how the defendant was just 17 when he set up the far right organisation and specifically targeted the young and impressionable.
Its members would regularly train in woodland in Wiltshire and other locations and were put through physical fitness challenges. Some had weapons training.
Within a few years, the group had reached national prominence, staging sometimes violent protests in towns across the UK, in support of a neo-Nazi ideology.
Detective Superintendent Anthony Tagg, from the West Midlands Counter Terrorism Unit, who led the investigation into Alex Davies and other members, said the group was determined to cause widespread division in society.
“National Action clearly sought to espouse hatred and division within communities across the country.” He said.
“They sought to identify difference and to amplify that difference. They held a similar ideology to the Nazi Party in Germany during the 1930s and 40s.
“They believed in the hatred of Jews and held anti-Semitic views.
“They sought out young people who were vulnerable, vulnerable because they are exploring and trying to understand their place in the world.
“They sought to exploit that vulnerability for their own aims, to radicalise them into this right-wing neo-Nazi ideology.”
Undated handout photo issued by West Midlands Police of a Reservoir Dogs-inspired poster showing members of National Action
West Midlands Police
The government moved to proscribe National Action in 2016, after its members encouraged far-right attacks on politicians, following the murder of Labour MP Jo Cox.
But even after the group was outlawed, Alex Davies and other members set up offshoot groups NS131, Scottish Dawn, System Resistance Network and TripleK Mafia, all with the intention of getting around the ban.
Superintendent Tagg said: “The risk National Action presented was clear. Through their recruitment, they sought to identify individuals in what they considered to be positions of authority - within the likes of the British Army and within policing.
“They gathered together weapons, gathered together the material about the creation of explosive devices.
“One of them had created a pipe bomb and was prosecuted successfully for that. So we say that National Action and those individuals within the group were incredibly dangerous, and the ideology they espoused was an ideology of hatred.”
In total 19 people have now been convicted for their membership of National Action.
They Include Alice Cutter, whose adoration of the Nazis was so profound, she even entered a Miss Hitler beauty pageant, and spoke of gassing synagogues.
Her boyfriend Mark Jones was jailed for five-and-a-half years for his involvement in the group.
In 2016, he caused international outrage after posing for a picture alongside Alex Davies inside the former Buchenwald concentration camp in Germany. The photograph showed the pair holding a National Action flag and making a Hitler salute inside the Buchenwald gas chamber.
Undated handout photo issued by West Midlands Police of Alex Davies doing a Nazi salute with a convicted member of National Action
West Midlands Police
Metropolitan Police officer Ben Hannam was jailed last year, after being convicted of his membership of the group.
Even as he applied to join the police, he was still meeting regularly with the group, training, posting fliers and spray painting extremist propaganda on buildings.
The organisation also recruited members of the military, like Mikko Vehvilainen, a lance corporal in the Royal Anglian Regiment, who was jailed for eight years.
Jack Renshaw, 24, was jailed for life for a plot to murder the Labour MP Rosie Cooper.
The common factor with almost all of Alex Davies’s National Action recruits was their youth, either in their teens or early 20s.
Security analyst Duncan Gardham said Davies “had worked out how to target the propaganda element of the recruiting process at young people and how to make the most of the Internet and how to make the most of memes".
He added: “They took their message out into the community. He took particular aim at university campuses and also held rallies in towns that might be ripe recruiting grounds for him.”
Assessing the danger National Action posed, Duncan Gardham said many of its members were set on a course towards violent extremism.
“They essentially wanted to target MP's and particularly female MPs who were, in their view, supporting the immigration that they so objected to.
“And they were also stockpiling weapons and organising training camps. And it was really the violent element of this group that started to worry the government and the security services.
Almost a decade after National Action was formed, founder Alex Davies and many of its members are now behind bars.
Islamist extremism is still by far the most potent threat facing the UK, but authorities say far-right extremism remains a key and growing concern.
