The internal Labour Party report which concluded Jeremy Corbyn’s attempts to tackle antisemitism were hampered by factional hostility was commissioned by the party's General Secretary Jennie Formby, ITV News can reveal.

Formby, a close ally of Corbyn, worked on the report which was intended to serve as an annex to the full submission that is being sent to the Equalities and Human Rights Commission, as they investigate the party over allegations of antisemitism.

The work for this 860-page report was managed by Formby and was written and overseen by a handful of others who worked in the party’s Governance and Legal Unit (GLU) – most of whom are also allies of the former Labour leader.

I’m told new Labour leader Sir Keir Starmer was given this report last week before it was in the public domain and was informed that the party’s lawyers were advising against its submission.

Jennie Formby, pictured hugging Jeremy Corbyn, commissioned the leaked report. Credit: PA

After the document was leaked to the media, Starmer ordered an independent investigation, saying the report “raised serious concerns”.

I now understand a separate internal investigation into how the document was leaked has been launched by the party.

Despite disagreement among members, Labour's National Executive Committee (NEC) gave Formby approval to manage and not share details of the EHRC submission - of which this report was a part.

Tom Watson, who at the time was deputy leader, asked for all work being done as part of the EHRC submission to be shared – a request that was repeatedly denied.

Senior figures within the party, Seamus Milne, Karie Murphy and Andrew Murray, the latter of whom was seconded to the party from Unite, all provided information, evidence and emails that related to the allegations of anti-Semitism to aid research for the submission, but did not help to write this report.

Every member of staff at Labour HQ who had any knowledge or involvement in the allegations was asked to do the same – in what I’m told is in requirement with the EHRC request of full disclosure.

The research for the report granted the writers access to staff members' emails and they looked at approximately 100,000 while compiling the report.

One source told me that by chance they “found much more than they bargained for.”

In one case a senior Labour staffer had sent themselves their entire WhatsApp conversation history – which included group chats of colleagues at Labour HQ discussing their opinions about Corbyn and Labour’s performance at the 2017 general election.

Some of the conversations included “abusive and inappropriate language about the leader, MPs, Labour members and about other staff”, the report claims.

In a joint statement responding to the report, Starmer and Labour deputy leader Angela Rayner said: “We have also asked for immediate sight of any legal advice the Labour Party has already received about the report.

“In the meantime, we ask everyone concerned to refrain from drawing conclusions before the investigation is complete and we will be asking the general secretary to put measures in place to protect the welfare of party members and party staff who are concerned or affected by this report."