UKIP has suspended three members after an attack on a socialist bookshop in which far-right protesters allegedly chanted fascist songs and threatened staff.

The pro-Brexit party said it believed three of its activists were involved in an incident at the Bookmarks shop in Bloomsbury in central London on Saturday.

The shop reported that twelve people, one wearing a Donald Trump mask, entered just before closing time, knocking over displays, ripping up magazines and chanting.

Bookmarks, which is now planning a free public “solidarity” event with author visits this Saturday, said it had been inundated with messages of supports after the attack.

Noel Halifax, 67, one of the two staff in the shop on Saturday evening, said: “There were a dozen of them bellowing and saying that we are this, that and the other and it’s a disgrace. One was saying something like ‘We wish you burn down’.

“They were very shouty, bellowing in your face, saying incoherent things. They were wearing baseball hats saying ‘Make Britain Great Again’.”

There had been a demonstration earlier in the day in London against censorship of the far-right conspiracy website Infowars.

In a statement, Ukip said party chairman Tony McIntyre has suspended Elizabeth Jones, Luke Nash-Jones and Martin Costello pending an investigation.

“It is understood that the three members were involved in an incident at the Bookmarks bookshop in London on Saturday,” it said.

There were no arrests and no reports of any injuries following the incident.