The decommissioning work will be carried out by contractors which will initially include British Nuclear Fuels and United Kingdom Atomic Energy Authority. The agency said that it is highly conscious of the fact that decommissioning will present unpredictable challenges which will depend on advances in science and technology to resolve.

Sir Anthony Cleaver, NDA Chairman said: “Many of the UK sites - whether built for research or power generation - have reached or will shortly reach the end of their active lives. The nature of the decommissioning process means these facilities cannot simply be switched off and demolished, but will take many decades to decommission.

“One of the issues we face is the limited information available on how the sites were planned, designed and built. Unlike the more modern plants, decommissioning was not necessarily considered back in the 40s, 50s and 60s and many of the plants were built to a variety of designs, with many one-offs.”

John Haddon, Cogent’s Nuclear Skills Adviser said: “The separation of the cleanup liability for state owned nuclear sites into a single body is welcome and Cogent is engaging with the NDA and its contractors to ensure that the skills and the competence frameworks for this activity are in place as they are needed.

“The operating nuclear power stations still provide an essential part of the electricity used in the UK and should continue to do so as long as they can do so safely and economically. The skills for operation and maintenance of the power stations must be maintained and Cogent will be a partner and support to the employers in this next phase. “

The launch of the NDA represents the start of a project that will cost an estimated £48bn and could take more than 100 years to complete.