Exclusive: Labour lawyers decide an 860-page dossier on failures to handle AS complaints, compiled in last months of Corbyn's leadership, should not be sent to the EHRC.
Some close to Mr. Corbyn are furious, with one saying: "the truth must come out"
An extensive internal investigation into the way Labour handled antisemitism complaints will not be submitted to the Equality and Human Rights Commission, after an intervention by party lawyers.
The 860-page report, seen by Sky News, concluded factional hostility towards Jeremy Corbyn amongst former senior officials contributed to "a litany of mistakes" that hindered the effective handling of the issue.
The investigation, which was completed in the last month of Jeremy Corbyn's leadership, claims to have found "no evidence" of antisemitism complaints being treated differently to other forms of complaint, or of current or former staff being "motivated by antisemitic intent".
Instead, the report concludes there was a lack of "robust processes, systems, training, education and effective line management" and found "abundant evidence of a hyper-factional atmosphere prevailing in Party HQ" towards Jeremy Corbyn which "affected the expeditious and resolute handling of disciplinary complaints".
As well as 10,000 separate emails, the dossier uncovers thousands of private WhatsApp communications between former senior party officials and singles out for criticism some who gave whistleblower evidence to last year's highly-critical BBC Panorama investigation on antisemitism within Labour.
These include the former General Secretary Lord McNicol and the former acting head of the governance and legal unit, Sam Matthews.
However, Sky News understands party lawyers have told General Secretary Jennie Formby the report entitled: "The work of the Labour Party's Governance and Legal Unit in relation to antisemitism, 2014 - 2019", should not be submitted to the Commission, due to fears it could damage the party's wider case.
A Labour Party spokesperson disputed the suggestion the report was ever intended to be submitted to the EHRC, saying:"The Party has submitted extensive information to the EHRC and responded to questions and requests for further information, none of which included this document."
But that decision has prompted widespread concern amongst those who worked in the most senior positions in the leadership office of Jeremy Corbyn, with one telling Sky News: "This report completely blows open everything that went on".
"We were being sabotaged and set up left right and centre by McNicol's team and we didn't even know. It's so important that the truth comes out", the source added.
A report found factional hostility towards Jeremy Corbyn amongst former senior officials contributed to "a litany of mistakes".