By 73%-27%, the 550 members of the Prospect union have voted in favour of strike action, and by 84%-16% in favour of action short of a strike.

The yard’s Prospect branch will later this week inform management it will call the first of a series of strikes for early August, followed by a work-to-rule and further strike action later in the month, said Alan Denney, Prospect National Secretary.

Other unions at the yard, representing all its 1,200 workers, have been balloting and are also expected to take part.

The dispute is over Babcock’s imposition of a series of changes to the dockyard pension scheme, including a 4.5% increase in pension contributions, cuts in pensionable pay and an increase in the retirement age to 65.

Denney said it was not too late for the company to meet with unions and avert the action, which will hit the yard’s ongoing programme of ship refits.

He warned: "Imposing changes to terms and conditions is not the way to conduct industrial relations in the 21st century. Members in other Babcock companies will be paying close attention to the actions of management at Rosyth.

"If the company wants to deliver on its share of the aircraft carrier contract it has just won from the Ministry of Defence it will have to treat its workforce with a bit more respect than a modern gangmaster."