Security services have cracked down on a group of far-right activists targeting a Jewish MP and an anti-Semitism chief, after a neo-Nazi was arrested in Somerset and ten more were rounded up in Liverpool.

Joshua Bonehill, 21, was detained last Thursday night on suspicion of harassment in connection with the hate campaign against Luciana Berger MP and John Mann MP, the chairman of the All-Party Parliamentary Group against Anti-Semitism.

Shadow Health Minister Luciana Berger.

Shadow Health Minister Luciana Berger.

It comes after nine men and a woman were arrested on suspicion of conspiracy to cause criminal damage in the early hours of Saturday 1 November outside Berger’s Liverpool offices.

Both Mann and Berger have received abusive messages via social media in a campaign involving an American blog called The Daily Stormer, the creation of white supremacist Andrew Anglin.

In it he says: “Berger should be deported to her home country of Israel and that John Mann should be arrested for the acts of espionage and treason.”

Mann recently called for the “wholesale re-evaluation” of Twitter’s procedures for tackling abuse in a speech to parliament in which he revealed that he had been targeted for raising the issue of Berger’s abuse.