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 company said if the strike affected the safety or stability of its operations it would be “forced” to accelerate closure plans.

The strike will begin on 8 July at Port Talbot and Tata’s Llanwern site in Newport.