law has been passed to curb the effect strikes can have on some key services.
The Strikes (Minimum Service Levels) Act has been granted Royal Assent, having cleared both Houses of Parliament after a protracted battle over its impact.
The law will allow ministers to impose minimum levels of service during industrial action by ambulance staff, firefighters, railway workers and those in other sectors deemed essential.
It has faced strong opposition from unions and opposition parties in Parliament, but the House of Lords relented in its stand-off with the Government on Thursday.
Labour has pledged to repeal the law if it gets into government.
It comes as hospital consultants go on strike across England, causing large-scale disruption to patient care, while a walkout by rail workers in a long-running dispute brought fresh travel chaos for train passengers.
Business minister Kevin Hollinrake claimed the new law provided an “appropriate balance between the ability to strike, and protecting lives and livelihoods”.
He added: “The UK remains a world leader for workers’ rights and these new laws will not prevent a union from organising industrial action.”
Meanwhile, rail minister Huw Merriman said the Act would “help give passengers certainty that they will be able to make important journeys on a strike day”.
But the Trades Union Congress (TUC) vowed to fight it “tooth and nail”, and claimed it would damage workers’ rights.
TUC general secretary Paul Nowak said: “The Conservatives are threatening to take a wrecking ball to our fundamental right to strike.
“No-one should be sacked for trying to win better pay and conditions at work – especially in the middle of a cost-of-living crisis. But that is exactly what this draconian legislation will allow.
“These new laws will give ministers the power to snatch away the right to strike from a massive one in five workers – that’s 5.5 million people.
“Make no mistake, the TUC will fight this pernicious legislation tooth and nail – exploring all options including legal routes.
“We won’t stand by and let workers get sacked for defending their pay and conditions.”
The Act had been caught in the parliamentary tussle between the Commons and Lords known as ping-pong, with peers concerned about the lack of detail within the legislation.
Making clear his continued opposition in the House of Lords earlier in the day, Labour peer Lord Collins of Highbury said: “This is a skeletal Bill. An example of legislating and then determining policy and procedure. It’s really the wrong way round.”
He added: “I repeat the intention of a future Labour government to repeal this Act. Because it doesn’t have the support of workers’ representatives or employers.
“It’s impracticable and it will simply result in not achieving the objectives of the Bill as the Government set out, but worsening the situation in industrial relations.
“Even the Government’s own impact assessments have said it could possibly increase strikes.”