The Board of Deputies and the Community Security Trust have called on Ukip to dissociate itself from an American far-right website that spreads George Soros conspiracy theories and claimed the US government may have been behind the Pittsburgh synagogue attack.
In June, Paul Joseph Watson, who is a "editor at large" at Alex Jones' Infowars website, was welcomed into Ukip earlier this year as a member as part of an attempt by leader Gerard Batten to make the party more appealing to young voters.
Mr Watson has more than 1.4 million followers of his YouTube channel and he made a video praising Ukip after joining the party alongside Mark Meechan, a self-described comedian and free speech activist.
After the Pittsburgh attack, in which 11 people died, Mr Jones suggested it was the work of "the deep state", adding the government may have been "planning with groups they control to stage terror attacks".
