The Trades Union Congress (TUC) says it is reporting the UK government to the United Nations watchdog on workers’ rights over a new strikes law.
New rules on strikes will require some employees to work during industrial action – or face being sacked.
The TUC said the legislation fell short of international legal standards.
The government said the new rules “protect the lives and livelihoods of the general public” as well as access to public services.
Once implemented, the Strikes (Minimum Service Levels) Act will apply to a wide range of workers, including those in the rail industry and emergency services.
The TUC labelled them “anti-strike laws” and, as representatives from 48 unions gathered on Sunday, its general secretary, Paul Nowak said they’re “unworkable” – and may be illegal.
Speaking on the opening day of the TUC Congress in Liverpool, Mr Nowak said the union body will be lodging the case at the International Labour Organisation (ILO) because the new law “falls far short” of international legal standards.
The government took forward the legislation following a year of unprecedented industrial action by hundreds of thousands of workers, including nurses, teachers, civil servants and railway staff.
A spokeswoman for the government said: “The purpose of this legislation is to protect the lives and livelihoods of the general public and ensure they can continue to access vital public services during strikes.”
She added: “The legislation does not remove the ability to strike, but people expect the government to act in circumstances where their rights and freedoms are being disproportionately impacted, and that’s what we are doing with this Bill.”
The government pointed to research which suggested 600,000 medical appointments have been rescheduled over the past year, and £1.2bn in output has been lost, due to strikes.
A public consultation is under way into how the laws, which received Royal Assent in July, will be implemented by employers, but trade unions may well challenge them in the courts.
Under the new law, which will apply to England, Scotland and Wales, the government would set minimum service levels after a consultation.
Employers will then be able to issue a “work notice” to unions, setting out who is required to work during a strike.
Under the legislation, there would be no automatic protection from unfair dismissal for an employee who is told to work through a notice but chooses to strike.
If a strike is not conducted in accordance with the new rules, employers would be also be able to sue unions for losses.