Eight former Labour staff members – including the party’s ex-general secretary Iain McNicol - have accused Jeremy Corbyn and his closest aides of frustrating attempts to deal with antisemitism cases by exerting massive political influence.

A widely-anticipated BBC Panorama to be broadcast tonight also reveals leaked email chains which show current general secretary Jennie Formby attempting to influence the selection of the panel for the case of Jackie Walker, who was under investigation for antisemitism.

On 5 May 2018, an email sent by Ms Formby stated: “The NCC cannot be allowed to continue in the way that they are at the moment, and I will also be challenging the panel for the Jackie Walker case.”

Copied into these emails was Jeremy Corbyn (at his personal email address), Seumas Milne, the Leader’s Director of Communications and Karie Murphy, the Leader’s Chief of Staff.

Later, referring to the email chain, Ms Formby wrote – to the same email group: “I’ve permanently deleted all trace of the email. Too many eyes all on my Labour address. Please use my Unite address.”

In the programme, former general secretary Iain McNicol is shown the emails and responds: “The emails that you’ve shown me are really important…

"The issues that are raised within them should ring alarm bells across the party.

"The NCC was created in a specific way to remove itself from politics and from the political interference.  So, to try to interfere politically within the NCC is just wrong.”

Panorama also spoke to Mike Creighton, Labour’s former Head of Disputes, who says he was approached by Mr Corbyn’s Director of Communications, Seumas Milne, for advice in spring 2016: “[Milne] said, I want to talk to you about antisemitism, how we deal with it.

"And I gave him my advice, which as I recall was two things; one was, we should deal with some of the top level antisemitic cases much more swiftly and much more robustly.

“Second thing I suggested was that it would be the right time for Jeremy Corbyn as leader, to make a significant speech on the issue of the Middle East, particularly saying that Israel had a right to exist.”

Mr Creighton said Mr Milne laughed at his suggestions. “He actually laughed at me… I thought he actually wanted to know how we tackle antisemitism within the Labour Party.

" I think what he actually meant to say was, how do we deal with the bad publicity we’re getting?”

The programme reveals that in an email on March 10 2018 Mr Milne said there should be a review of the disciplinary process into antisemitic complaints: “Something's going wrong, and we're muddling up political disputes with racism... I think going forward we need to review where and how we’re drawing the line.”

The then Head of Disputes, Sam Matthews, interpreted that email as “the Leader’s Office requesting to be involved directly in the disciplinary process. This is not a helpful suggestion, it is an instruction.”

Dan Hogan, an investigator on the Disputes Team, describes the impact of Jennie Formby becoming the General Secretary in March 2018.

On a number of cases he worked on, people she brought in “overruled us and downgraded what should've been a suspension to just an investigation or worse to just a reminder of conduct, effectively a slap on the wrist.”

Panorama also reveals that there was an order from the Leader’s Office to bring batches of antisemitism complaints from Party HQ to Mr Corbyn’s office in parliament for processing by his aides.

The Labour Party said in response: “This is a staff resourcing matter. Staff have been seconded into GLU (the Governance and Legal Unit) at various times and from a variety of different departments in the organisation.

"These staff were always under the management of GLU staff while carrying out this administrative work. This in no way contradicts the separation of functions within the organisation and it does not contradict the Party’s position that the complaints process operate independently of the Leader’s Office.”

The whistleblowers deny they are politically motivated, as accused by Labour and supporters of Mr Corbyn.

Kat Buckingham, the former Chief Investigator in the Disputes team, said that the problem of antisemitism complaints was “massive” and “real” and “wasn't constructed by embittered old Blairites as we were frequently described as….. It would make no difference because …we had standards, we had clear rules that we had to try and uphold.”

She told BBC Panorama she had a breakdown and decided to leave the Labour Party – “I was stuck between …an angry and obstructive Leader's Office and an arcane disciplinary system… I couldn't hold the tide and I felt so powerless and I felt guilty and I felt like I failed …and yeah I had a breakdown.”

Louise Withers Green, former Disputes Officer left Labour after being signed off with depression and anxiety. In return for not having to work her notice period she signed a Non-Disclosure Agreement (NDA).

She said: “(The NDA) was really tight. When I first read it, I wondered how on earth I’d be able to apply for jobs because it was so prescriptive in not speaking about anything that I had heard of or happening in the Labour Party.”

She said she defied the NDA because she wouldn’t “be able to live with myself unless I speak up about the horrendous things that I know have been happening.”

In response to the Panorama programme, a Labour Party spokesperson said: “The Labour Party at all levels is implacably opposed to antisemitism and is determined to root out this social cancer from our movement and society.

"Labour stands in solidarity with Jewish people and is fully committed to the support, defence and celebration of the Jewish community and its organisations.

“Jeremy Corbyn has a long and principled record of solidarity with the Palestinian people and it is false to claim that he has associated with extremist groups. Jeremy Corbyn has proactively addressed antisemitism within the Party in direct communications to the Party membership, in articles, speeches, videos and interviews.

“The Leader’s Office did not intervene. These former disaffected employees sought the view of staff in the Leader’s Office, which was compiled with in good faith.

These disaffected former officials include those who have always opposed Jeremy Corbyn’s leadership, worked to actively undermine it, and have both personal and political axes to grind.

"It is simply untrue to say that there were any significant number of disagreements about what constituted antisemitism.

“The emails… are simply about ensuring the NCC is held accountable for the length of time they take to hear cases and about protecting the Party against any successful legal challenge on the basis of perceived bias if the same panel is used in high profile cases.

“Labour is taking decisive action against antisemitism, doubling the number of staff dedicated to dealing with complaints and cases. And since Jennie Formby became General Secretary, the rate at which antiwemitism cases have been dealt with has increased four-fold.”