About 1,500 Tata Steel workers will begin an indefinite strike next month over the company’s plans to cut thousands of jobs, the trade union Unite has said.
The move is the first time in more than 40 years that steel workers in the UK have taken strike action, the union added.
About 2,800 Tata Steel workers will lose their jobs when the company closes both blast furnaces in Port Talbot by the end of September.
The strike will begin on 8 July at Port Talbot and Tata’s Llanwern site in Newport.
Sharon Graham, Unite general secretary, said Tata’s workers were “not just fighting for their jobs – they are fighting for the future of their communities and the future of steel in Wales”.
She said the strikes would continue until the firm “halts its disastrous plans”.
Unite members at Tata previously observed an overtime ban and “work to rule” – meaning refusing to do work that is optional in their contracts.
Tata has urged Unite to suspend the action and return to discussions along with other unions.
The company plans to build a £1.25bn electric arc furnace to produce steel in a way which is less polluting than traditional blast furnaces, but requires fewer workers.
Tata said the move would secure the future of steel making at the site and the UK government is contributing £500m towards the cost of the project.