Liz Truss has been urged to “come clean” over her plans for workers’ rights if she becomes prime minister, amid reports she is planning a post-Brexit shake-up of employment laws.

The Times reported on Saturday that the Foreign Secretary, widely seen as the frontrunner in the race to replace Boris Johnson, is eyeing up a review of protections for workers.

The paper suggests the rules covering the 48-hour working week, adopted first as part of the EU working time directive, could be among the protections reviewed by a Truss administration in a bid to improve UK competitiveness.

Trades Union Congress general-secretary Frances O’Grady said Ms Truss should “come clean” about any such plans.

“Liz Truss’s number one priority should be to help families pay their bills this winter,” Ms O’Grady said.

“Threatening hard-won workers’ rights is the last thing the country and working people need.

“She must come clean about her plans.

“Holiday pay, equal pay for women and men, safe limits on working hours and parental leave are just a few of the rights underpinned by retained EU law. These are vital workplace protections and rights – not nice-to-haves.

“Leading Conservatives – including (Business Secretary) Kwasi Kwarteng – repeatedly promised to make Britain the best place in the world to work and to enhance workers’ rights. That promise now appears in tatters.

“Rather than dealing with the cost-of-living emergency, ministers seem more interested in attacking workers’ terms and conditions.”

Ms Truss will inherit a daunting set of challenges if she does defeat rival Rishi Sunak to become prime minister, with a worsening cost-of-living crisis and soaring energy bills threatening to cause widespread misery for households this winter.

She will also be under pressure to resolve ongoing strikes by criminal barristers and further walkouts by rail workers, as well as the threat of industrial action in other sectors this winter.

The Foreign Secretary was criticised previously during the leadership campaign after leaked audio revealed she had said British workers need to display “more graft”.

Labour deputy leader Angela Rayner said the reported plan shows how “out of touch” the Government is, and she accused Ms Truss of wanting to take a “sledgehammer” to workers’ rights.

Ms Rayner said: “First the leaked recording showed how little she thinks of British workers, now she has shown her true colours with a plan that would rip up their rights and see workers who are already pushed to the brink during a cost-of-living crisis have their holidays reduced.

“She is out of touch and out of step with the public.”