“We can confirm that a number of serving members of the Army have been arrested under the Terrorism Act for being associated with a proscribed far right group,” a spokesperson said.
“These arrests are the consequence of a Home Office Police Force led operation supported by the Army.
“This is now the subject of a civilian police investigation and it would be inappropriate to comment further.”
West Midlands Police said the suspects are a 22-year-old man from Birmingham, a 32-year-old man from Powys, a 24-year-old man from Ipswich and a 24-year-old man from Northampton.
A spokesperson added: “They have been arrested on suspicion of being concerned in the commission, preparation and instigation of acts of terrorism under Section 41 of the Terrorism Act 2000; namely on suspicion of being a member of a proscribed organisation, National Action.
“All four men are being held at a police station in the West Midlands.”
“The arrests were pre-planned and intelligence-led - there was no threat to the public’s safety.”
Section 41 gives police the power to arrest anyone “reasonably suspected to be a terrorist” without warrant.
West Midlands Police would not give further details of the men’s activities but the “commission, preparation and instigation” of terrorism encompasses a wide spectrum of acts include directly planning an attack, joining a prohibited group or giving effect to that intention.
The arrests come months after a far-right terror cell was uncovered in the German army.
A Bundeswehr soldier was found to have posed as a Syrian refugee for more than a year as part of an elaborate plan to launch a “false flag” terror attack that would be blamed on asylum seekers.
The man, named by prosecutors as Franco A, was also a suspected neo-Nazi.
An assault rifle case carved with a swastika was found in his room, where the letters HH [Heil Hitler] were inscribed on the wall and a Nazi-era pamphlet depicting a Wehrmacht soldier was discovered.
A second German soldier was arrested in relation to the plot amid fears of a wider neo-Nazi network within the country’s army, sparking a government investigation.
National Action became the first extreme right-wing group to be banned in the UK in December, but investigations have shown its members are still meeting in secret.
The Government’s list of proscribed terror groups describes it as “a racist neo-Nazi group” that was established in 2013 and had several branches in the UK that launched provocative protests and activity aimed at intimidating local communities.
“Its activities and propaganda materials are particularly aimed at recruiting young people,” the document says.
“The group is virulently racist, anti-Semitic and homophobic. Its ideology promotes the idea that Britain will inevitably see a violent ‘race war’, which the group claims it will be an active part of.
“The group rejects democracy, is hostile to the British state and seeks to divide society by implicitly endorsing violence against ethnic minorities and perceived ‘race traitors’.”
National Action, which describes itself as a ”National Socialist youth organisation“, was known for using the phrases ”Hitler was right“ and ”Britain is ours, the rest must go“ at marches and online.
Its online propaganda included images showing members performing Hitler salutes inside a German concentration camp, praise for the man who murdered Jo Cox and posts “glorifying terrorism”.
Being a member of National Action or inviting support for the group is a criminal offence carrying a sentence of up to 10 years imprisonment.
Amber Rudd, the Home Secretary, said the organisation had “absolutely no place in a Britain that works for everyone”.
Speaking in December, she said the ban hoped to prevent its membership from growing and curtail the ability of its “poisonous propaganda” to radicalise vulnerable young people.
While counter-terror efforts in the UK are largely focused on Islamist extremism, the number of suspect far-right radicals flagged to an anti-terror programme has soared.
Just under a third of all people being monitored under the Channel programme in 2016/17– part of the Prevent terror prevention scheme – believe in extreme right-wing ideologies and are vulnerable to radicalisation, according to unpublished Home Office figures.
Following the terror attack targeting Muslim worshippers in Finsbury Park, which left one man dead, the security minister warned that online propaganda was fuelling both jihadi and far-right extremism.
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