Far-right vigilantes are drawing up databases of asylum seekers living in houses of multiple occupation (HMOs), fuelling fears of violence across the country after properties were attacked in Thetford.

Norfolk Constabulary is investigating how houses that were targeted over several nights of disorder last week were identified, after residents had to be evacuated when mobs smashed windows and attempted to force their way inside.

A Refugee Council official said the events amounted to a “pogrom” and could be repeated as HMOs become an increasing focus for anti-migrant activists.

A man in his sixties has been arrested over the sharing of addresses in Thetford, but on social media calls are circulating for databases to be drawn up of asylum accommodation nationwide.

‘First the traitors, then the invaders’