Strike action at Dounreay nuclear power plant has widened as a second union voted to stage a walkout over pay.

It was announced on Thursday that members of the GMB had voted to strike, with 450 set to walk out.

Unite and Prospect were also balloting members at the site near Thurso, and members of the former have also backed a strike.

On a turnout of 82.3%, 85.5% voted to walk out due to a pay offer described as 'inadequate', 4.5% effective from April 2023 which was previously rejected by 95% in a consultative pay ballot. 

The trade union has warned that strike action will be ‘inevitable’ in the coming weeks and that owner Magnox Limited has a ‘final opportunity’ to resolve the dispute by making a revised pay offer to the workforce.

Unite general secretary Sharon Graham said: “The Dounreay workforce have overwhelmingly backed industrial action because NRS (now Magnox) has repeatedly failed to make them a fair pay offer. At the same time, the company has found the time to feather the nests of its directors. 

"Unless NRS quickly gets back round the negotiating table to make our members an offer they deserve, then industrial action will be inevitable. Unite will fully support our members at Dounreay power station in the fight for better jobs, pay and conditions.”

Following the union's own ballot, GMB Scotland senior organiser Keir Greenaway said: “Given the economic situation, our members have not been offered a pay rise at all but a real terms pay cut.

“Managers insist they are bound by civil service rules but apparently can pick and choose which rules to follow.

"They seem far more relaxed when it comes to their own pay, for example.”

A Dounreay spokesperson said: "We are disappointed by the result and remain committed to working with the unions to find a resolution that is fair and affordable.

"While we hope industrial action can be avoided, we will now enact contingency plans to ensure minimum staffing levels are in place to maintain safety, security and environmental protection during any period of disruption.”