Labour leader Jeremy Corbyn has spoken out against plans to restrict public sector strikes following a protest march in Cardiff.
He accused the Tories of “taking away the most effective means of securing better pay and working conditions” with the Trade Union Bill.
Mr Corbyn said he was “proud” of the work unions did trying to create a “decent collective society”.
Around 400 people took part in the march on Saturday.
The Labour leader did not march himself, but addressed campaigners when they returned to their starting point at the steps of the city’s National Museum.
Speaking from the top of a fire engine, Mr Corbyn said: “We’ve been through some terrible struggles, such as the miners’ strike in the 80s.”
He said workers continued to struggle in different ways, and defended their right to strike.
As it stands, the law allows strikes to be called if the majority of those taking part in a ballot vote in favour.
The new bill, currently being considered by the House of Lords, would only allow strikes in key public services if they were backed by at least 40% of union members eligible to vote in the ballot.
The UK government has said it wants to ensure essential services are not disrupted at short notice by strikes supported by a small proportion of union members.
First Minister Carwyn Jones has threatened to defy Westminster by passing Welsh laws on strikes, even if it results in a Supreme Court battle over where responsibility lies.
Speaking before the event, Mr Corbyn said: “I congratulate the Welsh Labour government on their work to stand up for trade unionists in Wales.
“Welsh Labour, unlike the Conservatives in Westminster, know that strong public services rely on a well-trained, safe and decently-paid workforce.”