Nuclear workers at the Dounreay site are to be balloted over strikes in a row over pensions.

Around 16,000 members of several trade unions across the UK, mainly involved in decommissioning work, will vote in the coming weeks on whether or not to launch a campaign of industrial action.

The unions are protesting at plans by the Nuclear Decommissioning Authority to make savings of £660m.

Staff at Dounreay Site Restoration Ltd, based in Caithness, are among those being balloted.

The firm is responsible for demolishing and cleaning up the former research centre.

Workers at other sites will also be balloted, including those at Hunterston A in Ayrshire, Chapelcross in Dumfries-shire, Sellafield, Magnox, Essex and Cumbria.

The unions said the UK Government's expectation is final salary pension schemes in place across the NDA estate will be reformed by April 2018.

Justin Bowden, national officer of the GMB, said: "Nuclear workers have played their part in keeping the country's lights on for decades.

"Senior representatives were unanimous that if this government is determined to break its promises and is not prepared to negotiate, there is no alternative but to ballot members to take strike action.

"GMB remains committed to resolving these issues amicably and available for meaningful talks should the government want to pull back from this shocking episode of broken promises to workers in the nuclear industry."

A Nuclear Decommissioning Authority spokesman said last week: "Government policy is that all public-sector final salary pensions schemes should be reformed by 2018, and four million public sector workers have already moved to new pension arrangements.

"Specific decisions on how to change the Nuclear Decommissioning Authority's estate pension schemes have yet to be taken. We expect to begin formal consultation on January 9, 2017."