Ken Livingstone has identified “the Jewish vote” as a contributory factor in Labour’s poor showing at the ballot box.
The former mayor of London admitted Jeremy Corbyn would have to resign imminently over his failure to deal with anti-Semitism.
Mr Livingstone, who quit the party last year amid a torrent of allegations of anti-Semitic behaviour against him, told the PA news agency: “The Jewish vote wasn’t very helpful.
“Jeremy should have tackled that issue far earlier than he did.
“It looks like the end for Jeremy, which is disappointing for me since I’m a close ally. I’m sure he’ll have to resign tomorrow.”
The issue of anti-Semitism within the Labour party dogged Mr Corbyn during the election campaign.
The matter came under even sharper focus following the unprecedented intervention of the Chief Rabbi, Ephraim Mirvis, who said that the “overwhelming majority of British Jews are gripped by anxiety” at the prospect of a Labour government.
Mr Livingstone was originally suspended in 2016 after claiming in a radio interview that Hitler had supported Zionism in the 1930s.