Prospect represents engineers, scientists and managers at: AWE, the Trident warhead manufacturer; specialist civilian staff at Faslane, the home base for the Vanguard submarines that carry the Trident missiles and at BAE Systems in Barrow-in-Furness where the UK submarine fleets are designed and constructed.

Deputy general secretary Garry Graham said: “If the conclusion is that the UK’s interests have been well served by having an independent nuclear deterrent and that in these uncertain times there is a need to retain that deterrent capability, then that capability needs to be credible.

“Against that backdrop the only credible option is for the UK to maintain its continuous at sea deployment of the deterrent. The idea that our deterrent capability can operate on an ad hoc basis, or is something which can be switched on and off, depending on circumstances, is fanciful.”

“From an economic stand point, investment in a like for like Trident replacement is essential for re-invigorating the UK’s defence infrastructure. It already supports many thousands of the most highly skilled jobs in Britain that help keep the UK at the forefront of science and technology development. They in turn support many more thousands of ancillary and support jobs around the UK,” said Graham.