Left-wing candidate Rebecca Long-Bailey has said that shadow cabinet files were deleted by a frontbench Labour colleague who resigned during the 2016 leadership challenge.

The contender to replace Jeremy Corbyn in the ongoing internal election was speaking at a retirement party for Ronnie Campbell, the former Labour MP for Blyth Valley who retired last month.

Long-Bailey appeared to suggest that a member of the shadow Treasury team in 2016 deleted shared files when MPs stepped down en-masse shortly before a leadership challenge took place.

She told the audience how she watched Rob Marris, then MP for Wolverhampton South West, resign from his shadow ministerial role during a committee meeting in parliament. Long-Bailey said he “flounced off”.

Describing the unfolding events, the Corbynite frontrunner added that she had a “feeling that something wasn’t right” and rushed back to her office where a staff member told her that shared files had gone.

The Salford and Eccles MP said: “I went in and I spoke to John [McDonnell] and I started ranting and I think my exact words were, ‘if they think they are going to get rid of us then they’re going to have to carry me out kicking and screaming’. And I sat in that office until about 3am going through all the clauses.

“Richard Burgon was dragged in at one point. Angela Rayner was dragged in and she got us a Domino’s pizza because we were starving. And we got through the clauses and we went to the finance bill committee the next day fully prepared, and I was pretty good if I’m honest.”

She added: “I don’t ever want to see anything like that again. We can never have anything like that happening again.”

@RLong_Bailey on top form at Ronnie Campbell’s retirement do in Blyth with a powerful insight into her part in the Shadow Treasury operation during the mass resignation of Labour MP’s clearly shows how strong & able she is to lead in high-pressure situations like this#RLB4Leader pic.twitter.com/OFzNPBOkv4 — John R Taylor (@JOHNROYTAYLOR) January 27, 2020

Marris has told HuffPost UK that his assistant deleted the files because they were not the property of the party. Commenting on the statement made by Long-Bailey, the ex-MP said: “She is trying to imply I stole Labour Party information.”

He added: “My assistant removed from the computer documents which my office created using my parliamentary expenses. That information was not paid for by the shadow Treasury team, it was paid for by parliament and it belonged to me.”

Fellow leadership candidates Keir Starmer and Lisa Nandy were serving on Labour’s frontbench at the time, and joined the ‘coup’ – stepping down from their respective roles during the spate of resignations.

Successive announcements of shadow frontbench and junior Labour MPs culminated in the 2016 leadership election, in which Owen Smith lost to Corbyn.

Long-Bailey also told audience members at the event that she had been expecting a hung parliament as the “worst case scenario” at the 2019 election, according to a recording leaked to HuffPost UK.

“We had a few wobbly people on the doorstep because of Brexit, but I thought everything was going to be alright,” the Shadow Business Secretary said.

Long-Bailey has explained that her leadership campaign initially got off to a slow start because she had been working on the getting Labour into government rather than preparing a “ready-made” bid for the top job.

Update, January 30th: Rob Marris has written a comment piece to point out that Long-Bailey’s story is inaccurate as the committee was not the next day but almost five days later. Her team has issued a response that says Long-Bailey “actually worked through the night for 5 consecutive nights and over the weekend… as months and months of work had been deleted by Rob Marris & his team”.