Organisers of a free speech rally in Boston on Saturday are warning far-Right groups to stay away amid growing fears of a repeat of the violent clashes that led to the death of a protester in Virginia last weekend.

The national director of the Ku Klux Klan has said members are expected to turn out for the event, due to start on Boston common at midday.

And police, already preparing for the presence of thousands of counter-protesters, said they were stepping up their vigilance in the wake of Thursday’s terrorist attack in Barcelona.

The result is a city preparing for the worst.

John Medlar, of Boston Free Speech which is organising the rally, said he was as shocked and horrified as anyone else at the violence in Charlottesville when white supremacist groups protested the removal of Confederate statutes commemorating the Civil War.