Seven Sisters, a long, thin council ward in the north London borough of Haringey, borders the Orthodox Jewish area of Stamford Hill. At a meeting of the local Labour Party in October 2016, they discussed the problem of street prostitution. “The only reason there are prostitutes in this ward is because of the Jews,” said one of the activists.

“No one said a word. No action was taken,” said one senior Haringey Labour member. “Everyone, including him, just carried on with the discussion, and it was one of countless examples, including things like open hate material being shared on the Tottenham Labour Facebook forum. A new set of norms has been created in the Haringey Labour Party.”

Momentum, the hardline Jeremy Corbyn supporters’ group, consolidated