Rebecca Long-Bailey has been accused by a former Labour MP of telling a “self-serving” and “inaccurate” story about his resignation forcing her to work late.

The Labour leadership candidate has accused Rob Marris, who served as a shadow Treasury minister alongside Long-Bailey in 2016, of leaving her in the lurch by quitting the frontbench and deleting files needed to hold the government to account the next day.

Marris quit the Labour frontbench on June 30, 2019 – as MPs sought to oust Jeremy Corbyn as party leader.

But writing for HuffPost UK on Thursday, Marris said he had “deliberately” tried to give Long-Bailey “ample time” to prepare for a parliamentary debate on finance bill once he was gone.

“Her account of what happened is very inaccurate. It is self-serving, and demonstrably not true,” he said. “Does this careless aspirant leader not do any basic research?”

He added: “She has not done the basics to check the accuracy of her faulty memory.”

Long-Bailey told a private dinner last week that Marris’s resignation meant she had to work through the night to be ready for the finance bill the next day. “I was pretty good if I’m honest,” she joked to the audience in Blyth.

But in reality the crucial legislation was not actually examined in the Commons until five days later.

A spokesperson for Long-Bailey said: “Rebecca recalls her and her staff having to work all through the weekend including during the night until 3am each day until the next sitting day, which commenced on Tuesday at 9am.

“The shadow Treasury team divided up the clauses of the finance bill, produced briefings and put them all on a shared drive.

“The finance bill was 191 clauses and each clause had to be researched, stakeholders engaged, and a speech in response needed to be drafted, amounting to months of work.

“But towards the end of the first day of the committee Rob Marris resigned during a point of order at about 3.20pm, 49 clauses in.

“Following the session, Rebecca went up to her office to speak to Jeremy Corbyn, and when it transpired that the bulk of the files for the other clauses on the shared drive had been deleted, it became apparent that Rebecca alone would have to respond to the remainder of the bill.”

Marris admitted he had removed research from the shadow Treasury’ team’s shared drive. But he said he did so as he was no longer a member of the team – and still retained a copy.

“Neither Ms Long-Bailey nor anyone else ever bothered to ask me for a copy of that material,” he said. “It was her own choice not to ask.”

He added: “Ms Long-Bailey is not telling the truth about me, no doubt inadvertently. 

“She ought to apologise forthwith. It is worrying that her memory is once again so faulty, and this raises doubts about her suitability to be Labour leader, let alone prime minister.”

Marris was the Labour MP for Wolverhampton South West from 2015 until 2017.