Jeremy Corbyn’s former chief of staff boasted about her involvement in attempts to force out MPs and union officials who had stood up against antisemitism, the JC can reveal.

A series of damning phone messages shown to this newspaper confirm that Karie Murphy admitted being personally involved in moves to “trigger” the deselection of the MPs who quit Labour in February last year citing Mr Corbyn’s failure over antisemitism.

After seven Labour MPs quit the party in February 2019 - including Luciana Berger, Angela Smith, Mike Gapes and Chuka Umunna - Ms Murphy wrote: “F**king idiots. All the work I did to trigger them and they leave before I had the pleasure.”

In another WhatsApp message, Ms Murphy, who was in charge of Labour’s 2019 General Election campaign, also admitted involvement in a successful move to have a union official who had previously called for the party to adopt the IHRA definition of antisemitism removed as chair of the party’s equalities body, the National Executive Committee (NEC).

After Keith Birch of the Unison union was replaced on the NEC by a left-wing representative, Ms Murphy wrote on January 30 last year: “We took out Keith so Unison are p***ed.

“He has been a c**t for years.”

On Wednesday afternoon Labour confirmed they had launched an investigation into Ms Murphy's messages.

A party spokesperson said:"Labour takes all complaints extremely seriously and they are fully investigated in line with our rules and procedures, and any appropriate disciplinary action is taken."

Further messages confirm the involvement of the close ally of Mr Corbyn and Unite union chief Len McCluskey in the long-running attempts to have MPs who were seen as unsupportive of the leader axed from their positions.

On February 18 2019, Ms Murphy was informed by a senior party official of the decision by seven MPs, led by the Jewish ex-parliamentarian Luciana Berger, to quit the party.

She responded: “You having a laugh.” 

When the party official suggested it was not a laughing matter, Ms Murphy then attacked Angela Smith - one of the MPs who left the party to form The Independent Group (TIG).

Ms Murphy then wrote: “Angela Smith is a moron. Getting rid of her made my day.”

But a few weeks later, on April 1, Ms Murphy then made clear how she herself had been working to force so-called “trigger ballots”, which would have put the exiled MPs at risk of being voted out of their posts by left-wing members of local Labour branches.

Referencing the TIG group of MPs, Ms Murphy wrote: “F**king idiots. All the work I did to trigger them and they leave before I had the pleasure.”

After leading the exit from Mr Corbyn's  Labour  Ms Berger said the party had become institutionally antisemitic and she was "embarrassed and ashamed" to stay.

The former Liverpool Wavertree MP was repeatedly threatened with the possibily of facing a "trigger ballot" by hard-left members of her local party.

At one point she was summoned to appear at a meeting to be grilled over her views on Mr Corbyn despite being heavily pregnant with her second child.

The replacement of Unison’s Mr Birch with the left-winger Ann Henderson on Labour’s NEC was openly celebrated by the pro-Corbyn camp in January 2019.

Tellingly, a story posted on the pro-Corbyn blog Skwawkbox on January 23 last year  read: “In the more significant change, CLP representative Ann Henderson has replaced Unison’s Keith Birch as chair of the equalities subcommittee and therefore in the important Officers group, which plays a large role in deciding the NEC’s priorities and programme. Henderson was elected to the NEC as a member of the left slate.”

Last October Ms Murphy was moved aside as Corbyn’s chief of staff  after clashes with colleagues – and a disagreement over the botched attempt to abolish former deputy leader Tom Watson’s job, on the eve of the party’s conference.

After the election defeat she landed a new role with former general secretary Jennie Formby as “executive director for governance, membership and party services”.

But after Sir Keir Starmer became leader she was moved out the role.

But she remains close to Ms Formby, with the pair posting a picture of themselves out to dinner with another leading Corbyn staffer, Amy Jackson, last week on social media.

In August Mr Corbyn lodged a complaint with the Cabinet Office after his recommendation for Ms Murphy to be given a peerage was rejected by the independent House of Lords appointment commission.

Insiders believe that the nomination of Ms Murphy – the former Executive Director of the Labour Party's Leader's Office -  was blocked in light of the investigation by the Equality and Human Rights Commission into Labour’s handling of alleged antisemitism.

Ms Murphy was quoted in recently published book 'Left Out', about the Corbyn years, saying: “I did not persuade Jeremy on IHRA. That was his decision and I always respected his decision as leader.”

The JC has also contacted Ms Murphy for comment over the WhatsApp messages.