"The UK’s strategic defence interests must be protected in all circumstances and this cannot be done by wishful thinking. In a world where more states have nuclear weapons than ever before, the UK must decide whether its own security is enhanced or reduced by maintaining a nuclear deterrent.

"As the union representing scientists and technologists working on the deterrent, both for the Ministry of Defence and private contractors, Prospect has always supported multilateral nuclear disarmament. The British public has never favoured a policy of unilateral reductions and our members don’t believe we should do so now."

But if the UK is to maintain a deterrent, it is essential for safety reasons to maintain the science, said Noon. "Nuclear components have different shelf lives and they must be constantly monitored to ensure they are stable. That means the UK must maintain its own independent scientific facilities in this field. Buying them in will not do."

On skills, the Prospect leader pointed to the high scientific and technological content of the workforce engaged on Trident, from skills in design and development, hydrodynamics and lasers to marine technology, nuclear power and specialist support. More than 13,000 UK defence workers are engaged on maintaining the existing deterrent, at the Atomic Weapons Establishment, Aldermaston; the Faslane/Coulpart naval base on the Clyde; and at Devonport dockyard.

"The UK needs every high-skilled worker it can get," said Noon. "Whatever the decision, this scarce science and engineering capability must be maintained. Its loss would be a body blow to research and development not just in the defence sector but for UK industry as a whole."

For the same reason, Noon rejected any suggestion that the submarine carriers for the next generation of deterrent should be built overseas. "The UK has the technology, the facilities and the workforce to build its own successor to the current Vanguard fleet. If Britain is to have a deterrent, it must be British-built."