A group of prominent Jewish writers and artists have expressed their “bewilderment and disgust” with Labour’s handling of the antisemitism crisis engulfing the party.

The letter – signed by Howard Jacobson, Simon Sebag Montefiore, Sir Simon Schama, Neil Blair, Tracy Ann Oberman and Rabbi Julia Neuberger – claims that antisemitism has been “protected, sanctioned and propagated by the leadership faction”.

The group argues the investigation into Labour by the Equality and Human Rights Commission, in regards to the handling of antisemitism complaints within the party, has shamed Labour in a similar way to the British National Party, which faced a similar inquiry in 2010.

“The very fact that Labour is, like the BNP before it, being statutorily investigated by the Equality and Human Rights Commission for racism is not a matter of housekeeping but a taint of international, historic shame,” the letter reads. “It is clear this is not just about [Labour leader] Jeremy Corbyn, but the pernicious world view of a faction that has – temporarily we hope – taken control of Labour.

“Trust between Corbyn’s Labour and most Jews in Britain appears to be fractured beyond repair.”

Draining the antisemitism that lies like a pool of poison in the party’s soul is the first priority for Labour

The letter comes after Wednesday’s Panorama programme alleged that high-ranking party members had interfered in the complaints process for antisemitism allegations. This included allegations that officials brought in by Labour general secretary Jennie Formby had interfered in disciplinary processes by overruling and downgrading suspensions related to antisemitism by party members.

However, Labour has denied the claims and said that it is taking decisive action against antisemitism. It states that since Formby became general secretary, the rate at which antisemitism cases have been dealt with has increased more than four-fold. It described antisemitism as a “repugnant form of racism”.

Eight former Labour employees participated in the programme, including former head of disputes Sam Matthews.

Matthews said he considered killing himself due to working conditions under the party leadership. Labour officially responded to the programme by claiming that the whistleblowers were not being truthful and “had a political axe to grind”.

The letter released today said Labour’s response to the whistleblowers flew in the face of Labour party tradition. “Whistle blowers would be heroes to any other Labour Party; to this Labour Party they are traitors,” it read. “After Panorama, damage limitation should not be the first priority for Labour.

“Draining the antisemitism that lies like a pool of poison in the party’s soul is.”

Labour heavily criticised the programme again in a statement yesterday, claiming it “had no political balance of interviewees, invented quotes and edited emails to change the meaning.” The statement added: “The programme completely failed to interview balancing voices who could provide a fuller and less biased and overtly politically one-sided view on this important issue.”

Formby has said she was “very concerned” to hear about the distress suffered by some of the former staff members, adding that she had not been made aware of those issues at the time.

It is expected that more than 30 whistleblowers, including current Labour staff, will submit evidence to the EHRC antisemitism inquiry.