That was the stark warning issued by Prospect, Britain’s biggest nuclear union, following the launch of the NDA strategy.

On behalf of 11,000 professional workers in the nuclear industry, Prospect National Secretary Mike Graham said: "While we welcome the strategy as it gives a focus to the decommissioning work, the NDA have failed to grasp that the most important threat is the number of skilled people leaving the industry.

"Measures to retain existing expertise and assure new entrants that the industry can provide a viable and rewarding career are needed right now. Otherwise there will not be enough people with the right qualifications and experience to carry out the decommissioning challenge."

Graham said it was ironic that the strategy would boost the number of back office jobs as the companies put in place human resources, project management and administration support needed for each tender while the technical expertise ‘dwindles away’.

Prospect deplores the government’s decision to sell the British Nuclear Group (BNG) rather than seek a Public Private Partnership. But Graham said it remained essential that any future owner, along with the successful competitors for NDA contracts, meet six key tests in the interest of public safety and the workforce.

"The news that Sellafield, the Reactor Sites and Project Services will be sold as a whole, rather than fragmented and left open to a disastrous asset stripping-exercise, has been welcomed by our 6,000 members in BNG.

"But it is essential that the new owner is of the same calibre as BNG and has an established track record in the fields of health, safety, security and environmental performance.

"Proven ability at effective change management and good industrial relations will also be vital for the success of the new employer."

But, he added, questions remain over the impact the BNG sale may have on Risley, which houses many research and engineering skills supporting Sellafield, and the BNFL group office at Daresbury.

The union will be pressing for assurances over their future, particularly given the threat to the skills base and has raised the issue with Warrington MPs.