Hundreds of nuclear workers have taken strike action in a protest over pay. 

Workers from Sellafield Ltd took part in yesterday’s 24-hour strike forming picket lines at three of the plant's gates, creating long tailbacks for those travelling to the site.

The GMB union, which represents the 371 health physics monitors who took the action, said that its members deserved a universal pay rise, while Sellafield Ltd maintains that any increase should be based on merit.

Joe Murdock, GMB convenor on site, said: "The decision to strike hasn't been taken lightly, but it sends a strong message that our members are aggrieved and feel they deserve the recognition of the pay upgrade they had been promised.

"The company has had many opportunities to resolve this but has declined any meaningful discussions with us."

The dispute centres on the criteria of a pay rise pledged to the monitors negotiated in January last year.

More than 83 per cent of the monitors took part in a ballot for industrial action on July 6 and almost 98 per cent voted in support of action.

Monitors, who assess radiological conditions, are thought to receive an average salary of £40,000 per year and, like all Sellafield Ltd staff, received a 2.2 per cent pay rise in April.

Rory O'Neill, Sellafield Ltd's stakeholder relations director, said that the company is "focused on fairness" in its pay negotiations.

He said: "We feel that monitors are fairly recompensed for the job they do. The cream of the crop probably deserve more, but we don't agree with a blanket uplift."

The GMB agreed that the legal minimum of 17 monitors remained on site during the strike.

Members held six-strong picket lines on the site's Calder, north and main gates, displaying banners including: 'We are sorry for the delay - blame the company'.

Mr Murdock said that the strike had the "desired effect" in terms of disruption to the site, while Mr O'Neill claimed that internal disruption had been "fairly light" and safety levels had been maintained.

Gridlocked roads were largely confined to the vicinity of the site, and Mr Murdock added that the date had been chosen to coincide with the school holidays so the wider community was unaffected.

Mr Murdock and Mr O'Neill said their respective organisations were open to further negotiations.