Labour’s civil war over antisemitism allegations has deepened after close Corbyn ally Diane Abbott retweeted a call from a senior party official for deputy leader Tom Watson to consider his position.

The party’s chair of disputes, Claudia Webbe – a member of Labour’s ruling National Executive Committee – said Mr Watson’s public criticism of general secretary Jennie Formby while she was having cancer treatment was “not behaviour befitting of the office of deputy leader”.

Her message was one of a series of posts attacking Mr Watson.

Ms Abbott retweeted one of the posts but later attempted to distance herself from the call for his resignation, pointing out that her Twitter profile states that “retweeting does not mean agreement”. Her spokesperson added: “Diane does think it’s wrong to attack Jennie Formby, but she’s certainly not calling for Tom Watson to resign. Her own tweets set out her position.”

Mr Watson sparked anger among the party’s highest ranks by releasing a letter in which he raised concerns about the party’s “unacceptable” treatment of employees who had spoken out about antisemitism and called on Ms Formby to publish Labour’s response to an Equality and Human Rights Commission inquiry.

Accused of being ‘deeply irresponsible’: Labour deputy Tom Watson (PA)

Shadow chancellor John McDonnell said: “It goes beyond my understanding that he does so when he knows she’s undergoing chemotherapy”. Shadow justice secretary Richard Burton said Ms Formby “deserves better than unfair attacks”.

The message retweeted by Ms Abbott read: “@tomwatson, your engaged in public attacks on the Labour Party’s General Secretary @JennieGenSec despite your clear knowledge she is receiving chemotherapy treatment for cancer. This is not behaviour befitting of the Office of Deputy Leader. You should consider your position?”

Ms Formby hit back at Mr Watson, branding him “deeply irresponsible” and his actions “inappropriate”.

She claimed Jeremy Corbyn’s deputy was abusing his position and “traducing” her reputation during her chemotherapy.

As the backlash from the revelations of a BBC documentary continued, Mr Watson said that the whistleblowers involved had been “smeared” in a “deplorable” way by party officials. And he accused Ms Formby of withholding the party’s submission to the EHRC from him, the shadow cabinet and the NEC.

“Only sunlight can disinfect Labour of antisemitism now,” he wrote.

Jennie Formby is having treatment for cancer (AFP/Getty)

Replying in a letter, Ms Formby said she was “very disappointed” by Mr Watson’s behaviour, insisting she had twice offered to show him the party’s response.

“I am very disappointed at the way you choose to address this extremely sensitive and difficult issue. The party has at all levels consistently shown that it recognises the vital importance of combating antisemitism, yet you consistently abuse your considerable platform to denigrate any progress that has been made, and any individual that is involved in that”, she wrote.

“Furthermore, traducing my reputation and publicly attacking me when you know I am undergoing chemotherapy and am unable to respond in the media, is another example of the inappropriate way in which you choose to discuss this issue.”

The latest row broke out in the wake of a BBC Panorama investigation into Labour’s handling of antisemitism, which featured former party employees speaking out about their experiences.

Panorama investigates alleged Labour antisemitism: punishments were downgraded to a 'slap on the wrist', says Dan Hogan

The whistleblowers claimed they had been obstructed in their attempts to tackle antisemitism, and some said they had suffered mental health problems because of the difficulties they encountered at work.

Ms Formby told Mr Watson that she was “very concerned to hear for the first time the distress suffered by some of our former staff members” but accused him of commenting “uncritically” on the programme.

She said: “By choosing to ignore the steps taken by this party, and commenting so uncritically about the Panorama programme, you are complicit in creating a perception that antisemitism is more prevalent in the Labour Party than wider society.

“This is deeply irresponsible for the deputy leader of a party which seeks to be in government, and risks exacerbating the feat that Jewish communities will feel.”

Mr McDonnell also criticised Mr Watson, saying: “I just don’t understand why the deputy leader of the Labour Party uses the media to demand information from Labour’s general secretary which has already been offered to him.”

The Panorama documentary included the testimony of eight former Labour employees, four of whom broke non-disclosure agreements (NDAs) to speak out.

The former officials claimed that Mr Corbyn’s allies, including director of communications Seumas Milne and Ms Formby, had interfered with investigations.

Labour denied the allegations and complained to the BBC about the programme, claiming the broadcaster had “engaged in deliberate and malicious representations designed to mislead the public”.