Shop stewards for the four main unions at the yard decided to request the ballot on Wednesday 11 July. The result will be declared on 25 July.

Workers will be asked to vote on whether to back strike action and action short of a strike, with a strong recommendation from shop stewards to vote yes on both counts.

Last month work at the yard stopped when the entire Rosyth workforce walked out after Babcock management said it intended to impose a disputed 4.5% increase in pension contributions, reduce pensionable pay and raise the retirement age to 65.

Prospect National Secretary Alan Denney, representing more than 500 specialist engineering and technical staff, said the company had cancelled pay negotiations until the result of the ballot was known.

He predicted a substantial yes vote which would lead to a series of 24-hour stoppages starting in early August, with mounting impact on the yard’s ongoing refit programmes.

"Management must understand the depth of feeling on this issue among staff at the dockyard. It is not going to disappear. Imposing changes to terms and conditions and pensions 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," said Denney.