Set to an electro-pop soundtrack of The Prodigy, National Action targeted Britain's disaffected youth through slick online propaganda.

National Action was founded in late 2013 by university students Alex Davies and Benjamin Raymond and targeted men in their 20s.

It was based on neo-Nazi ideology and hatred of members of Jewish, gay and ethnic minority communities.

Pc Matthew Fletcher told jurors: "Part of white supremacy is preparation for the race war in their eyes, in their ideology."

The far-right group drew heavily on the "virulently racist" rhetoric and symbols of Adolf Hitler's Nazi party.

The black and white logo featured on flags was similar to that of Hitler's brown shirts.

Recruitment was through the internet and the distribution of leaflets at flash demonstrations, Pc Fletcher said.

Mr Davies was removed from Warwick University due to a sticker campaign there, jurors heard.

Stunts by activists included the desecration of the statue of Nelson Mandela in Parliament Square, placing a banana in his hand.

Propaganda videos of demonstrations across England and Scotland showed men in skull masks waving banners and making Nazi salutes.

National Action was banned for promoting the murder of Batley and Spen MP Jo Cox in tweets which called for her killer Thomas Mair's "sacrifice" not to be in vain.

But whistleblower Robbie Mullen said: "The politics was still the same - free white man. The group had gone, the name had gone, but the people were still meeting."

Leader Christopher Lythgoe, 32, from Warrington, was said to be in charge of propaganda and mixed martial arts training.

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He "decided everything", even instructing members to dress all in black at demonstrations, Mr Mullen said.

When he learned of the ban, he told members they had "shed one skin for another" as he took the organisation underground.

He promoted self defence at his gym for "whatever happens, if there was ever the race war", according to Mr Mullen.

He said: "Chris would do the basics and it would just be normal boxing, punching a bag and sparring."

Matthew Hankinson 24, of Newton-le-Willows, Merseyside, was in charge of "security" and was for some time Lythgoe's "number two", jurors heard.

In his sentencing, Mr Justice Jay said the case justified the then home secretary's view that National Action was "virulently racist, anti-Semitic and homophobic".

He said: "After 16 December 2016 National Action operated under the radar, hoping that the authorities would remain blind to its continued existence. It naturally shed its skin, and its public appearance, no doubt hoping that one day it might spring back into action."

Meetings at the Friar Penketh pub in Warrington provided a "focus" for post-proscription activities, and "keeping alive an aspiration which was truly insidious and evil".

Mr Justice Jay said: "The truly evil and dystopian vision ... could never have been achieved through the activities of National Action, a very small group operating at the very periphery of far-right wing extremism.

"The real risk to society inheres instead in the carrying out of isolated acts of terror inspired by the perverted ideology I have been describing."