Union leaders are urging the Government to act on an insecure work “free for all” when it responds to a review of working practices.

A response is expected in the next few days to the Taylor Review on Modern Employment Practices, which criticised “one way” flexibility in the workplace.

The TUC estimated that at least 1.8 million workers are at risk of missing out on rights including redundancy pay, protection against unfair dismissal, and the right to return to a job after having a baby because they are in insecure employment.

Many more are missing out on rights because their bosses have wrongly classified them as self-employed, unions believe.

TUC general secretary Frances O’Grady said: “The insecure work free-for-all has to end.

“Agency workers are being treated like second-class citizens, getting less pay for the same work and zero-hours contracts leave many workers unable to plan childcare or budget for their weekly shop.

“This will be a real test of Theresa May’s government. Does she even have a domestic agenda anymore? Or has her government been totally hijacked by Brexit in-fighting.”

The TUC is calling on the Government to ban zero-hours contracts, ensure equal pay for agency workers, crack down on bogus self-employment and increase resources and powers for enforcement.

Matthew Taylor, chief executive of the Royal Society of Arts, said in the review published last July that workers should have a right to request fixed hours and permanent contracts along with a requirement that companies disclose how they have responded to such requests.

He said there was nothing wrong with zero and low hours contracts but they should be a means to two way flexibility.