LABOUR’S internal strife over anti-Semitism has moved into a bitter new phase with calls for Tom Watson, the deputy leader, to resign.

Diane Abbott, the Shadow Home Secretary, has highlighted the calls on social media, retweeting a series of critical remarks about her Shadow Cabinet colleague, including one questioning his position.

The diatribes came after Mr Watson ramped up pressure on the party over its handling of anti-Semitism claims in the wake of this week’s damning BBC Panorama documentary.

Labour MPs Emma Dent Coad, Danielle Rowley and Ms Abbott were among those condemning Mr Watson, who wrote a critical letter to Jennie Formby, the party’s General Secretary.

Ms Abbott shared one tweet from a representative of the ruling National Executive Committee, criticising Mr Watson's treatment of Ms Formby.

"This is not behaviour befitting of the Office of Deputy Leader. You should consider your position?" Claudia Webbe's said.

Other tweets promoted by Ms Abbott included ones accusing Mr Watson of "appalling behaviour" and of undermining staff.

Ms Dent Coad expressed "solidarity" with Ms Formby, who was heavily criticised alongside Seumas Milne, Labour's Director of Communications, in the BBC report for allegedly interfering with anti-Semitism investigations.

"On the day a report on parliamentary bullying is published, Watson has been relentless. Shame on him," the Kensington MP tweeted.

Ms Rowley, who represents Midlothian, also launched an attack on Mr Watson, saying: “It’s disgraceful for Tom Watson to publicly attack @JennieGenSec while she is undergoing chemotherapy; a horrible and draining cancer treatment, which she took time out of to talk to Shadow Cabinet, and she has offered to meet with him. There is no need for this attack.”

Mr Watson had written to the General Secretary calling for the party to publish its submission to a watchdog investigating anti-Semitism claims and raising allegations that she had deleted emails relating to cases, which Ms Formby denies.

His letter came after eight former Labour officials told Panorama they had been undermined in their attempts to tackle the blight in the party.

Lord McNicol, the former General Secretary, and three others broke non-disclosure agreements by speaking out.

Labour has strenuously denied the claims and written a complaint to the BBC.

Mr Watson's letter said those who spoke to the programme were "very brave to go before a camera and tell their stories".

"The way that they have been smeared, including by Labour spokespeople, is deplorable," declared the Midlands MP.

"Even if some in the party did not want to hear what they had to say, it is unacceptable to attempt to undermine their integrity and characters in this manner," he added.