A neo-Nazi movement is to become the first extreme right-wing group banned as a terrorist organisation, the Government has announced.
An order laid in Parliament on Monday to proscribe National Action under the Terrorism Act 2000 is due to come into effect on Friday morning.
It will mean that being a member of, or inviting support for, the group becomes a criminal offence.
Announcing the move, Home Secretary Amber Rudd described National Action as a "racist, anti-Semitic and homophobic organisation".
Ms Rudd said: "As Home Secretary, I am clear that the safety and security of our families, communities and country comes first.
"So today I am taking action to proscribe the neo-Nazi group National Action.
"This will mean that being a member of, or inviting support for, this organisation will be a criminal offence.
"National Action is a racist, anti-Semitic and homophobic organisation which stirs up hatred, glorifies violence and promotes a vile ideology, and I will not stand for it.
"It has absolutely no place in a Britain that works for everyone."
National Action is being proscribed as it has been assessed to be "concerned in terrorism".
The Home Secretary decided to ban National Action before the trial of Thomas Mair, who was convicted of and jailed for the murder of Labour MP Jo Cox.
The phrase "Death to traitors, freedom for Britain!" - which was said by Mair in court - appears alongside the listing for National Action's website on Google.
In the wake of Mair's conviction, warnings emerged that there are signs that the terror threat from the extreme right could be growing.
Ms Rudd said last month that groups have become "increasingly sophisticated" in the use of social media for promotion and for recruitment.
Around a quarter of the cases being handled by the Government's counter-extremism programme Channel are for right-wing radicalisation.