A severe staff shortage affecting Britain's nuclear safety watchdog — almost five months after a government pledge to strengthen the organisation — threatens to delay plans to build a fleet of new nuclear reactors.

The Nuclear Installations Inspectorate (NII), a pivotal group in the new-build programme that has been handed the task of ensuring the safety of new reactor designs to be built in Britain, still has fewer than three quarters of the staff needed to do the job, according to figures from the Department for Energy and Climate Change.

They show that the NII has only 169 trained nuclear inspectors but needs 228 to complete its work. It is seeking to recruit 61 staff, equivalent to more than a third of its present level.

The figures have emerged four months after a government review warned that the NII, which is carrying out a regulatory study of the designs, was “significantly under-resourced for its predicted future workload”.

The review, produced in December by Tim Stone, a government energy adviser, also said that a failure to recruit new staff by the end of last month would “seriously jeopardise the delivery of a key element of this Government's energy policy ... the construction of new nuclear power plants by 2017 or beginning of 2018”.

The Government's plan for the new reactors is moving swiftly ahead. A list of provisional sites for new UK reactors is due next Wednesday and an auction for three government-owned nuclear sites is under way.

However, an industry insider said that the NII remained seriously under-resourced. “The sense in the industry is that the NII is not on track and that raises questions about the proposed timeframe,” the source said.

Yesterday the NII was still seeking to recruit nuclear inspectors and was advertising on its website for staff in 15 separate work areas, including chemical and electrical engineering, radiation protection and reactor faults. Potential recruits were being offered relocation expenses of up to £15,000 and travel expenses to attend interviews.

In recent months the NII, until recently a little-known part of the Health and Safety Executive, has been thrust on to centre stage in Britain's plans for a nuclear revival. Jean McSorley, a campaigner for Greenpeace, said: “It's a very crowded timeline. They are really up against it.”

Mr Stone, as well as calling for more staff, recommended pay rises for existing employees and offers of 25 per cent higher pay to recruits. The NII, based in Bootle, on Merseyside, may also open an office in the South East. Some of the proposals would require legislative changes.

The NII is due in November to publish its initial findings on the two reactor designs it is appraising for UK use — Areva's EPR reactor and Toshiba-Westinghouse's AP1000.

In a presentation dated February 23, David Watson, a senior NII inspector, said that the NII “will complete” its work by November 27, but admitted that the body had only 75 per cent of the specialists it needed.

The NII has been hit by defections to the private sector. To counter its staff shortage, it has had to recruit temporary staff from private companies and depend on work carried out by regulators in France and America.

A spokesman for the Department for Energy and Climate Change said: “We're confident the reforms are helping them build up capacity to deliver.”

A spokesman for the NII said: “The recruitment activity is ongoing, and if successful will enable the [design assessment] process to be delivered to the agreed June 2011 timescale.”

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