A pro-Palestinian lobbying group championed by Jeremy Corbyn is supported by Holocaust deniers and 9/11 conspiracy theorists, a report has ​claimed.​

Activists with the Palestine Solidarity Campaign (PSC) are accused of harbouring “hardcore anti-Semitic ideology”, according to the study.

It suggests that at certain PSC branches, some activists were found to have promoted “Holocaust denial”, “global Jewish conspiracies” and “classic anti-Semitic tropes”.

The study prompted calls for Mr Corbyn to quit as a ​PSC patron after two decades closely associated to the group.

Mr Corbyn is reeling from accusations he has turned a blind eye to anti-Semitic views held by his keenest supporters within Labour and has now apologised.

But it emerged on Tuesday that Mr Corbyn has ignored repeated requests since 2016 to meet with the all-party parliamentary group against anti-Semitism, which is chaired by the Labour MP John Mann.