John Mann has told The Sunday Times he was standing down after 18 years as a Labour MP

The Labour Party was plunged into civil war again this evening as a veteran MP revealed he is quitting the Commons to take up a full-time role as the government’s anti-semitism tsar.

John Mann told The Sunday Times he was standing down after 18 years as a Labour MP and said Jeremy Corbyn was unfit to be prime minister for his mishandling of the anti-semitism crisis that has engulfed the party.

His decision came as Diana Johnson became the first victim of Labour’s new trigger ballot process. After 14 years’ service as MP for Hull North, she will now face a battle to be reselected.

With Labour and the Scottish National Party (SNP) expected to block a general election tomorrow, Mann’s decision to quit raises