The UK government on Thursday announced new anti-strike legislation to enforce minimum levels of service in eight sectors including the NHS following widespread industrial action across the country.

The Trades Union Congress warned unions would “fight every step of the way” to block the government’s legislation, which aims to ensure public services function adequately during strikes.

Prime minister Rishi Sunak is contending with strikes in multiple industries — involving nurses, postal staff and train drivers — as workers demand higher pay amid the cost of living crisis.

Ministers put forward legislation before Christmas that would have imposed a minimum service agreement on the railways, with employers able to sue unions and sack staff if this were breached.

But on Thursday the government announced this legislation would be superseded by a bill that would impose “minimum safety levels” on multiple sectors.

The government said it would enforce these arrangements on ambulance, fire and rail services after a public consultation.

Ministers hope to reach voluntary agreements on minimum safety levels for other sectors covered by the bill — education, border security, nuclear decommissioning, other health services and other transport services.

But if voluntary deals cannot be reached the government would unilaterally impose the arrangements.

“The government has a duty to the public to ensure their safety, protect their access to vital public services and help them go about their daily lives,” said the government.

“The government will always protect the ability to strike, but it must be balanced with the public’s right to life and livelihoods.”

Under the legislation, employers will issue a “work notice” to specify the number of workers needed to meet minimum service levels during strikes.

If workers become involved in industrial action despite being included in the “work notice” they could lose the right to automatic protection from unfair dismissal.

The legislation is expected to face opposition in the House of Lords and cannot be implemented until the consultation is completed.

Sunak’s allies insisted the government would press ahead with the legislation regardless of the outcome of the wave of strikes, and that it was not a negotiating chip. “We believe there must be a minimum level of safety and service provided,” said one.

But ministers invited union leaders to “honest, constructive conversations”, urging them to “return to the table and call off strikes”.

They said they wanted to meet union leaders to discuss what could be “fair and affordable” in public sector pay settlements for the coming financial year of 2023-24. 

Sunak has so far not adopted proposals by business secretary Grant Shapps to force unions to give more notice of strikes and tighten rules on picketing.

But unions believe the new bill on minimum service levels, when combined with 2016 legislation that raised the threshold for strike votes to be valid, represents a draconian assault on their rights.

Paul Nowak, general secretary of the TUC, said it was “wrong, unworkable and almost certainly illegal” to force people to work when they had voted for industrial action, adding that unions would “fight this every step of the way”, both in parliament and in the courts.

Matt Wrack, general secretary of the Fire Brigades Union, said: “The Tories are clearly hell-bent on criminalising and victimising trade unions with this threatened onslaught on the right to strike.”

The GMB union called it a “desperate act” by a government “trying anything to divert attention from the chaos they have created”.

Other unions suggested that staffing levels in the NHS were safer on strike days than at other times because of local agreements involving employers.

“Safe staffing levels that are set in law are what we want to see year-round,” said Pat Cullen, general secretary of the Royal College of Nursing, adding the walkout by nurses last month had been safe for patients.

Darren Newman, an expert in employment law, said the absence of any clear guiding principle on what would constitute a minimum service level was a “yawning gap” in the legislation.

He added it looked unrealistic even after consultation for ministers to draft regulations in the detail required to cover all the NHS organisations, local transport networks and other employers potentially affected.

Labour leader Sir Keir Starmer said he would reverse the government’s legislation if he won the next general election.