BBC Scotland's Bob Dickson reports on the action

An overtime ban and a work to rule is also being planned by 1,200 members of the Institute of Professionals, Managers and Specialists at the Babcock-owned complex.

They are hoping to secure an improved pay offer with a series of two-hour stoppages at the end of each day's shifts.

The yard has just started a £150m refit of the aircraft carrier HMS Ark Royal, but a ballot on industrial action was backed by an overwhelming 95% of members.

Wide support

IPMS spokesman Alan Denney said refit work on two submarines and the Ark Royal would be hit by the action, which is being supported by a wide range of staff - including engineers, supervisors and designers.

Babcock has offered a 2.5% increase in salary this year followed by another 2.5% next April. But this was related to performance pay and there are cuts in sick pay and annual leave entitlement.

The company revised its offer but a union spokesman said this too was rejected.

"The revised offer still has too many strings attached to sickness benefit, shift working and overtime and was rejected a week ago," he added.

Strike ballot

"The management have made no further offer or attempted to have further discussions. This will be the first of a number of walkouts and if the company does not respond there will be an escalation of industrial action."

The remaining 2,000 industrial workers at the yard rejected a similar pay offer on Tuesday night.