The action is in protest against last month’s decision by the government to contract out the UK’s warship support services delivered by the Naval bases, resulting in the loss of around 1,000 of the 3,000 jobs to be privatised.

It follows a meeting between defence union representatives and MOD ministers on Wednesday where the unions repeated their dismay that a positive public sector alternative had been rejected. They also sought, unsuccessfully, to gain a delay in contract signing pending an independent scrutiny of the impact of the decision.

Prospect negotiator David Luxton, said: "Our members have always believed in the force of an argument rather than an argument of force. They were willing to cooperate with MOD to deliver in-house efficiencies but instead are being coerced into the private sector and an uncertain future.

"Today’s action reflects the great sense of anger among members following the ministry’s decision to contract-out warship support services in preference to the union plan which offered better value-for-money."

Ralph Groves, on behalf of PCS members, said: "Our members are striking because they feel betrayed by the government and the MOD. In deciding to contract out the jobs of loyal civil servants ministers have disregarded years of hard work and service.

"Alongside industrial action we will continue to press for full parliamentary scrutiny of the decision."

Members with essential safety responsibilities at the Naval base have been specifically excluded from the action. Initially planned for April 9, the strike was deferred out of respect for the Queen Mother’s funeral.

Notes:

The decision to contract out many of the functions of the Naval bases on the Clyde is part of government’s Warship Support Modernisation Initiative which affects the three main naval bases including Devonport and Portsmouth.

The defence unions are Prospect, PCS, Amicus, GMB, T&G and UCATT.