The government's decision to allow companies to hire agency staff to cover for striking workers was overturned on Thursday by the High Court, who upheld a legal challenge by 13 trade unions that it was unlawful.
The change to regulations last year, during an ongoing wave of disputes over pay and conditions, made it easier for businesses to use temporary staff during industrial action.
But the 13 unions, which represent around three million workers, argued Britain is breaching union rights with the regulations, the Conduct of Employment Agencies and Employment Businesses (Amendment) Regulations 2022, which they say could worsen industrial disputes and endanger public safety.
Judge Thomas Linden upheld the unions’ legal challenge in a written ruling on Thursday, and quashed the regulations with effect from 10 August 2023.
A spokesperson for the Department for Business & Trade said it was disappointed with the ruling and that the government was considering its next steps carefully.
"The ability to strike is important, but we maintain there needs to be a reasonable balance between this and the rights of businesses and the public," the spokesperson added.
Paul Nowak, General Secretary of the Trades Union Congress, called on the government not to appeal against the ruling.
"Ministers should spare themselves further embarrassment," he said in a statement. "These cynical strike-breaking agency worker laws must be scrapped once and for all."
Last year, then-business secretary Kwasi Kwarteng said the changes would remove "burdensome, 1970s-style restrictions" preventing employment agencies from supplying workers to replace those on strike, which was previously a criminal offence.
But the unions argued the government unlawfully made the changes without consulting them, instead relying on a 2015 consultation - which pre-dated Brexit, the COVID pandemic and the cost of living crisis.
Linden said in his ruling that there was virtually no consultation before the decision and Kwarteng "did not even consider the information available as to the responses to the 2015 consultation".
The trade unions welcomed the ruling, with Unite describing it as "a total vindication for unions and workers".
Paddy Lillis, general secretary of retail trade union Usdaw, said: “This victory for our members is a huge embarrassment for the government, showing that they are prepared break the law to break a strike. It is now time for ministers to drop their Strikes (Minimum Service Levels) Bill, which we also believe to be unlawful.”
“It beggared belief that, in the midst of a cost of living emergency, the Government engaged in ideological attacks on workers’ rights. Instead of undermining trade union members, the Government should be working with us on urgent plans to eliminate low-pay and insecure work.
Meanwhile, Prime Minister Rishi Sunak offered teachers, doctors and other workers pay rises of 6% and above, seeking to end months of crippling public sector strikes, but warned it would cost billions that might mean cuts elsewhere.
