Unite, a major UK union, represents more than 1,500 construction workers at the Cumbria site. They are taking action due to what they claim is their employers' refusal to agree to site-specific allowances for specialist skills. The industrial action is set to start on October 4 and will continue until October 13. "That this is the most significant industrial action at Sellafield in recent history speaks volumes about the levels of feeling among the workforce." A Sellafield Ltd spokesman said: "The industrial action taking place at Sellafield is the result of a pay dispute between some Unite union members and their employers.