Four British men, some of whom are serving British soldiers, have been arrested on suspicion of preparing acts of terrorism. They are all allegedly members of National Action, a banned neo-Nazi group.

The men, who were held on Tuesday, are a 22-year-old from Birmingham, a 32-year-old from Powys, a 24-year-old from Ipswich and a 24-year-old from Northampton.

The Ministry of Defence confirmed that “a number of serving members of the Army have been arrested under the Terrorism Act”.

West Midlands Police said the four men have been arrested on suspicion of terrorism offences, with a spokesman saying 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) contrary to sec 11 of the Terrorism Act”.

National Action became first extreme right-wing group to be banned under terrorism laws in December 2016.

The proscription meant that being a member of or inviting support for the organisation is a criminal offence carrying a sentence of up to ten years’ imprisonment.

All four men are being held at a police station in the West Midlands.