This montage shows the Labour leader with some of the anti-semitic, violent and misogynistic comments taken verbatim from the pro-Corbyn Facebook groups exposed by The Sunday Times

Jeremy Corbyn faces a damaging new anti-semitism scandal as a bombshell dossier reveals the full extent of anti-Jewish, violent and abusive comments on Facebook groups mobilising his most fervent supporters.

Twelve senior staff working for the Labour leader and the shadow chancellor, John McDonnell, are members of groups containing anti-semitic and violent comments, including praise for Adolf Hitler and threats to kill Theresa May, the prime minister.

The most comprehensive investigation conducted into 20 of the biggest pro-Corbyn Facebook groups — numbering 400,000 members — found routine attacks on Jewish people, including Holocaust denial.

The dossier was compiled over two months by whistleblowers working with The Sunday Times in the groups, who gained access to restricted membership groups. They uncovered more than 2,000 racist, anti-semitic,