A Labour frontbencher has suggested that Jeremy Corbyn might be hauled before an employment tribunal for “racial discrimination” if he worked outside politics.

Chi Onwurah, shadow minister for culture and the digital economy, accused the Labour leader of “picking on” her and another black woman MP, which she said was “statistically interesting, to say the least”.

She said Mr Corbyn had dealt with her and Thangam Debbonaire incompetently by splitting a job between them and then failing to properly communicate the changes.

“If this had been any of my previous employers in the public and private sectors, Jeremy might well have found himself before an industrial tribunal for constructive dismissal, probably with racial discrimination thrown in – given that only 5 per cent of MPs are black and female, picking on us two is statistically interesting to say the least,” she wrote in the New Statesman.

“Indeed, as Thangam was undergoing treatment for cancer at the time, he could have faced disability action as well. In any other job I would have called on my union for support in confronting an all-white management that prevented two of its few black employees from doing their jobs.”

Ms Onwurah remains in Mr Corbyn’s frontbench team but is backing Owen Smith for leader of the party.

A spokesperson for Mr Corbyn told The Independent: "Chi Onwurah's comments relate to a discussion about the delineation of Shadow Cabinet roles last January, as is not uncommon in both shadow cabinets and cabinets.

"Chi was appointed by Jeremy Corbyn to be shadow minister for culture and the digital economy last September. When Thangam Debbonaire was appointed as a dedicated shadow minister for the arts in January, there was a negotiation about the division of responsibilities with Chi and Thangam, but at no point was anyone sacked.

Chi Onwurah remains on the Labour front bench (Getty)

"We regret that Chi feels she was singled out, but this was clearly not the case."

The latest attack against Mr Corbyn comes as he lays out plans to increase democracy across society. The Labour leader said he would devolve more power to regions and local councils, introduce participatory budgeting, put workers on company boards, and democratise the party.

“I am determined to democratise our country from the ground up, and give people a real say in their communities and workplaces,” he said.

“We need to break open the closed circle of Westminster and Whitehall, and of the boardrooms too.

“Decisions in Britain are overwhelmingly taken from the top down. And that’s crucial to why our country is run in the interests of a privileged few.”

The announcement followed a further rift between Mr Corbyn’s supporters and Mayor of London Sadiq Khan – after Mr Khan’s name was booed at a rally in support of Mr Corbyn on Sunday night.

Labour leadership contest: Jeremy Corbyn vs Owen Smith Show all 8 1 /8 Labour leadership contest: Jeremy Corbyn vs Owen Smith Labour leadership contest: Jeremy Corbyn vs Owen Smith Jeremy Corbyn and Owen Smith clash at a leadership hustings in Gateshead, where Mr Smith was scarcely able to answer a question without being booed by Mr Corbyn’s supporters PA Labour leadership contest: Jeremy Corbyn vs Owen Smith “Jeremy himself admitted he was seven out of 10 in terms of his faith in the European Union. He said it,” said Mr Smith during his second live debate with Jeremy Corbyn Getty Labour leadership contest: Jeremy Corbyn vs Owen Smith Ballot papers are currently due to be sent out on 22 August and returned a month later, with the result being announced at a special Labour conference on 24 September Getty Labour leadership contest: Jeremy Corbyn vs Owen Smith Jeremy Corbyn supporters cheer and wave placards as the Labour Leader addresses thousands of supporters in in Liverpool, England Getty Labour leadership contest: Jeremy Corbyn vs Owen Smith Labour Party leadership candidate Owen Smith poses for a picture with supporters during a picnic for young members in London Fields, Hackney in London Getty Labour leadership contest: Jeremy Corbyn vs Owen Smith The Labour leader has a spring in his step at a leadership rally in Sunderland Screenshot Labour leadership contest: Jeremy Corbyn vs Owen Smith Labour leadership contender Owen Smith delivers a speech at the Open University in Milton Keynes, where he promised to reverse Conservative cuts set to leave millions of low paid workers thousands of pounds a year worse off PA Labour leadership contest: Jeremy Corbyn vs Owen Smith Shadow Chancellor John McDonnell has urged Owen Smith to distance himself from those saying they want to split the Labour party Getty

Meanwhile the leader’s rival Mr Smith sought to reassure left-wing Labour voters that the he would not tack to the political centre if he won the contest with new pledges on policymaking.

“I would bind myself to the decisions made by the party on party policy. I would not seek to overturn it,” he said in a speech in his home constituency of Pontypridd.

“Crucially I would give conference a new role and responsibility in our party to sign off on our manifesto.

“I believe it is necessary to reassure people across the party that there would be no backsliding on my watch and that the radical and credible policies I laid out in this leadership contest will be laid out in a manifesto, guaranteed.”

He also announced measures to strengthen the party’s policy forum, suggesting that affiliated organisations should be more closely involved in the process.

Left-wingers may still be wary of Mr Smith tacking to the right, however. He has made few pledges on immigration and welfare during the course of the contest – two areas Labour centrists believe the party needs to move rightwards on to win over swing voters.

New right-wing policies on these issues are still therefore consistent with Mr Smith following through on pledges made in the campaign.

Earlier in the campaign Mr Corbyn’s team accused Mr Smith of copying his policies on a number of issues.