Labour is facing a union backlash over reported plans to water down its package of workers’ rights in the coming weeks.

Unite general secretary Sharon Graham warned “a red line will be crossed” if the party U-turns on previous employment pledges while TUC president Matt Wrack said any weakening of policy will draw a “hostile reaction”.

Labour is set to announce all policies in its “new deal” for workers will go through a formal consultation process with businesses, which could delay their implementation or see them toned down, the Financial Times reported on Wednesday.

The party originally promised to bring forward legislation within its first 100 days in government to enact the reforms.

The report prompted a fierce response from union leaders, with Ms Graham saying: “Choosing May Day to give notice of watering down your promise to overhaul one of the worst sets of employment rights in Europe is beyond irony.

“If Labour do not explicitly recommit to what they have already pledged, namely that the New Deal for Workers will be delivered in full within the first 100 days of office, then a red line will be crossed.”

Mr Wrack told the FT: “My message is very clear, no rolling back… if there is any more rolling back on the New Deal, they can expect a hostile reaction to it.”

Labour will still promise workers basic protections from day one of employment but companies will be able to impose probationary periods and staff could be dismissed for “fair reasons”, according to the paper.

A party spokesperson said: “The New Deal will be a core part of Labour’s offer to the country and we will be campaigning on this ahead of the general election.

“Labour’s New Deal for Working People was agreed at the party’s National Policy Forum last summer building upon our Green Paper.

“Our commitments to bring forward legislation to Parliament within 100 days to deliver the New Deal and to consult widely on implementation have not changed.”

The New Deal would be the latest Labour policy to be scaled back after the party diluted its flagship £28-billion-a-year green spending pledge.

The Opposition blamed the Government’s handling of the economy when it confirmed the row-back in February, citing Liz Truss’s mini-budget in September 2022 and higher interest rates.

Conservative Party chairman Richard Holden said Labour were in “total chaos” over the plans, saying they would “cost British jobs and damage our economy”.

He said: “Labour’s 70 new regulations will ban flexible working, bring back zero warning strikes and disincentivise small businesses from hiring new staff. But Sir Keir Starmer cannot say whether it will be in their manifesto in full because he is too weak to stand up to his union paymasters or his out-of-control deputy.”