Labour's liaison with the Jewish community's Twitter account was identified as part of a pro-Corbyn "engine room" dismissing allegations of antisemitism, the JC has learned.
Heather Mendick, whose appointment to manage relationships with the community was widely condemned and led to Jewish groups refusing to engage with her, had a now-deleted account - @helensclegel - that antisemitism watchdog the CST listed among 36 influential accounts driving the online conversation around Jew-hate in Jeremy Corbyn's party.
These Twitter accounts had all claimed "that allegations of antisemitism in the Labour Party are exaggerated, weaponised, invented or blown out of proportion, or that Labour and Corbyn are victims of a smear campaign relating to antisemitism", CST's report said.
"Some have changed their position on these issues over the four years covered by this report, but all have, at one time or another, helped to build this narrative through the sharing of online content."
CST said 12 of the 36 accounts - but not Ms Mendick's - had themselves tweeted antisemitism.
The JC understands Ms Mendick’s Twitter account was deleted as CST and data analysis firm, Signify, were carrying out the research so it was not possible to analyse all of its output.
But a photo of one of the account's tweets show it expressed “solidarity” with Jenny Manson, the chair of the pro-Corbyn, fringe group Jewish Voice For Labour, which regularly seeks to rubbish claims of antisemitism in Labour.
The Jewish Leadership Council (JLC) said Ms Mendick had also defended MP Chris Williamson - who was ultimately suspended by Labour for claiming the party had been "too apologetic" over antisemitism.
The JLC said she also opposed the International Holocaust Remembrance Alliance definition of Jew-hate, which Labour only adopted after a protracted standoff with the Jewish community last summer.
Labour said it did not comment on "staffing matters" but a source in the party emphasised that CST's report “did not include [Ms Mendick's account] as one of the 12 accounts alleged to have tweeted antisemitic content”.
CST found the 36 accounts often promoted content from websites that have attacked allegations of Labour antisemitism such as The Canary, Swawkbox and Electronic Intifada.
"These websites provide the fuel for an atmosphere in which allegations of antisemitism are denied, while leading and encouraging attacks against anyone who criticises the Labour leadership for their record on the issue," the report said.
Its report was based on analysis of four years of tweets that have pushed pro-Corbyn messages under Twitter hashtags such as #GTTO – Get The Tories Out - #BoycottRachelRiley and #SackTomWatson.
Countdown presenter Ms Riley and Labour deputy leader Mr Watson have both spoken out repeatedly about Labour antisemitism.
When Ms Mendick's appointment was announced last month, it was was quickly condemned as “beyond parody” by the JLC, which noted she would only be liaising with the Jewish community one day a week.
A JLC spokesperson said noted her "dismissal of the IRHA definition of antisemitism... her support for Chris Williamson... her accusation that antisemitism was being ‘weaponised against the Left’", adding her appointment was "pitiful”.