Union boss Len McCluskey has addressed striking workers at the Faslane and Couport naval bases.

Civilian workers belonging to the Unite union at the Clyde bases have started a three-month period of staggered strikes which are expected to cause "major disruption."

Unite claims employers Babcock Marine are trying to undermine staff through outsourcing services to private companies. The union also claims workers' representatives are being undermined.

Babcock rejects the allegations and says it will try to minimise the impact of the strikes on operations.

On Monday, workers were bussed to a mass meeting in Helensburgh where Unite general secretary Mr McCluskey is set to address them.

He is currently running for re-election to the leadership of the union. Unite's West Midlands regional secretary Gerard Coyne and union convener Ian Allinson are also running for the post.

Speaking earlier, union officials said the Faslane strike would cause a "severe impact" at the bases, which are home to the UK's nuclear submarine fleet.

Regional officer Stephen Deans said: "This action will coincide with a particularly busy period at both Coulport and Faslane and will cause major disruption to the day-to-day services that Babcock Marine provides.

"This includes land-based repairs, mail delivery, feeding the Navy sailors at their normal mealtimes, and nuclear operational and waterfront services. There will be a severe impact.

"Our members work hard supporting the Royal Navy's operations. They refuse to be intimidated by a private company whose biggest interest at the moment seems to be weakening workers' rights so that it can squeeze all the cash it can from the nation's defence."

Babcock is set to meet union representatives this week for further talks.