A Jewish peer has said he will resign from the Labour Party if Jeremy Corbyn holds off a leadership challenge this autumn, citing his disappointment at the Chakrabarti Report into anti-Semitism.

Lord (Parry) Mitchell, 73, a former businessman who has funded collaborative efforts between British and Israeli scientists, described his intentions in a letter to The Times this week.

Describing allegations of anti-Semitism in the Labour Party “distressing,” he says: “Even more upsetting is the way Jeremy Corbyn dismisses what he has allowed to fester at the highest levels of our party.”

Lord Mitchell

Lord Mitchell

Mitchell goes on to dismiss Shami Chakrabarti’s investigation into anti-Semitism in the Labour Party, calling it “an insipid whitewash,” adding: “She seems to have done her master’s bidding of absolving the party of blame.”

The Labour peer, who is known for persuading the government to back an amendment to regulate payday lending in 2014, then said he would walk away from the party were Corbyn to continue as leader.

“I have come to the painful conclusion that were Mr Corbyn to be re-elected next month, I will have to resign my membership… I cannot remain a member of a party that goes against such a crucial issue that I hold dear.”

Mitchell was made a peer by Tony Blair in 2000, when he was a patron of Jewish Care and World Jewish Relief. He chaired Weizmann UK and the Coexistence Trust, which encouraged dialogue between Jewish and Muslim students on campus.