Hundreds of contractors at Sellafield will walk out next week in a row over pay – the same day 3,000 workers are also staging a strike.

Ancillary staff, employed by contractor Mitie at the nuclear site, will carry out a 24-hour strike on Wednesday.

The GMB union say Mitie, contracted by Sellafield to run facilities at the site, offered staff a 1 per cent increase earlier this year.

Members rejected the offer and were then offered a 2 per cent increase which was also rejected.

The staff carry out industrial cleaning and work such as catering, business services and security.

GMB members voted almost nine to one to take industrial action.

The strike comes on the same day 3,000 GMB members, employed by Sellafield, walk out in a separate dispute.

Chris Jukes GMB senior organiser said: "Our members working for Mitie at Sellafield do vital jobs that may not be seen by everyone in management as exciting or important, but the site cannot function effectively and safely without them.

"It is simply wrong that people doing hard, dirty and difficult graft at the sharp end on a nuclear plant should be in receipt of pay rates which many then have to supplement with in-work benefits.

"Our members are sick of falling behind other workers on site, they are sick of feeling betrayed and they are sick of a sense of low esteem.

"Some of our members work for between £7.65 per hour and £8.20 per hour on a nuclear site and deserve more given the highly sensitive nature of their work which can include working with cross contaminants.

"They are angry and frustrated at how they are treated. Mitie staff do hard working jobs and just want a fair reward for it."

A Mitie spokesman said: "Our team provide important services at Sellafield every day and we recognise the contribution they make at the site.

"We are actively engaged with GMB and are fully committed to ensuring the safe continuity and delivery of services at Sellafield, during any strike action."