Theresa May has joined calls for Labour MP Chris Williamson to be suspended after he claimed the party had been “too apologetic” over antisemitism.
Labour’s deputy leader Tom Watson has also written to the party’s general secretary and chief whip to call for Mr Williamson’s suspension.
But, Labour is so far refusing to withdraw the whip from the Derby North MP, who is a close ally of party leader Jeremy Corbyn.
A spokesman said: “Chris Williamson has been issued with a notice of investigation into a pattern of behaviour but has not been suspended.”
Footage from a Sheffield meeting of Momentum activists, obtained by the Yorkshire Post, shows Mr Williamson defending Labour’s record on antisemitism, saying it had “stood up to racism” but is “now being demonised as a racist, bigoted party”.
The Derby North MP said: “I think our party’s response has been partly responsible for that because in my opinion… we’ve backed off too much, we’ve given too much ground, we’ve been too apologetic.
“We’ve actually done more to address the scourge of antisemitism than any other political party.”
He also recounted singing 1980s hit Celebration, by Kool and the Gang, in response to the resignations of a number of Labour MPs last week, many of whom cited antisemitism as a reason for their departure.
Mrs May entered the row during Wednesday’s Prime Minister’s Questions, telling MPs: “They lose (Luciana Berger) and they keep (Mr Williamson).
“It tells you all you need to know about the Labour leadership: present but not involved.”
Ms Berger, who is Jewish, was among those Labour MPs to quit the party.
Mr Williamson posted an apology on Twitter during PMQs, saying he has always been anti-racist, and regrets his choice of words.
Citing his former membership of the anti-Nazi league and his direct work challenging antisemitic views, Mr Williamson said: “It pains me greatly, therefore, that anyone should believe that it is my intention to minimise the cancerous and pernicious nature of antisemitism.
“I deeply regret, and apologise for, my recent choice of words when speaking about how the Labour Party has responded to the ongoing fight against antisemitism inside of our party.
“I was trying to stress how much the party has done to tackle antisemitism.”
Since the MP’s apology, Mr Watson has released the letter he sent to Labour general secretary Jennie Formby and chief whip Nick Brown.
Mr Watson branded Mr Williamson’s comments “completely unacceptable”, adding: “It brings the party into disrepute and amounts to a Labour MP breaching the party’s code of conduct on antisemitism in a public forum.”
Mr Williamson is also facing criticism for booking a room in parliament to screen a controversial film about antisemitism titled Witch Hunt.
The documentary, directed by Jon Pullman, explores antisemitism allegations in Labour and defends activist Jackie Walker.
Ms Walker was suspended by Labour in 2016 after leaked footage showed her saying she had not found a definition of antisemitism she could work with.
The campaigner was also shown questioning why Holocaust Memorial Day was not more wide-ranging to include other genocides.
Ms Walker was removed as a vice-chair of Momentum, the pro-Corbyn group that grew out of his initial Labour leadership campaign.
Mr Williamson has previously described antisemitism “smears” as “a really dirty, lowdown trick” against Mr Corbyn, claiming many in the Jewish community are “appalled” by the “weaponisation of antisemitism for political ends”.
Labour MP for Sedgefield Phil Wilson said the remarks were “outrageous” and also called for Mr Williamson to be suspended.
He told Sky News: “When you’ve got an MP who’s expressing these views, I don’t think there’s any place for them – ultimately – in the Labour Party and we’ve got to be tough on them.”
It is understood Mr Brown and Ms Formby are in discussion about what action will be taken.
During the Momentum meeting in Sheffield, activists were heard applauding Mr Williamson’s comments.
A Momentum spokesperson said: “The Labour Party have called on Chris Williamson to apologise and we welcome that call.
“MPs should be held to the highest standards, and we trust that Labour’s general secretary and chief whip will determine an appropriate course of action moving forwards.”
Momentum chair Jon Lansman this week admitted there was a “major problem” with antisemitism within Labour and a “much larger number of people with hardcore antisemitic opinions” than first thought.