A Labour peer has warned he may leave the party unless its leadership sends out “a clear and unequivocal message” opposing antisemitism.

Lord Levy, president of Jewish Care, made the threat after Vicki Kirby was again suspended from the party for antisemitic tweets, activist Gerry Downing was excluded for a second time and another Oxford University Labour Club (OULC) officer quit after claiming the club was discriminatory.

Speaking on Sky News, the peer, who was a close advisor of former Prime Minister Tony Blair, said: “Antisemitism in any political party cannot be tolerated, and it is for the leadership to make that absolutely clear.

“If they don't make that clear, I will start to question that myself and actually question my being a Labour peer and a proud member of the Labour party.”

The lord added that “the leadership must come out with that message in absolutely a specific way, because from my perspective, being a member of this party, that is of paramount importance to me.”

OULC disabilities officer Brahma Mohanty resigned this weekend, claiming the club forced members to “subscribe to a radical ideology of division and isolation”.

This move followed the resignation of vice-chair Alex Chalmers last month , who said the club had a “problem with Jews”.

Vicky Kirby was suspended from the party following an investigation into a series of comments on social media in 2014.

But she was readmitted and selected as the vice-chair of Woking Labour Party’s executive committee last month, it was revealed last week.

Ms Kirby had been due to stand for Labour in Woking in the 2015 general election, but was dumped as a candidate after a series of tweets were posted from her account.

One message claimed Hitler might be the “Zionist God”. Another said: “We invented Israel when saving them from Hitler, who now seems to be their teacher.”

Gerry Downing was thrown out of the Labour party earlier this month following complaints that he had been re-admitted as a member.

A Labour spokeswoman said the decision to throw him out for a second time was made after further evidence came to light.

Mr Downing posted a tweet in 2014 referring to what he called “Hamas heroism”, appears to have questioned aspects of the Holocaust, and claimed prominent historian Ian Kershaw had a “Zionist minder”.