AWE is to remain under increased scrutiny by a government watchdog for the second year.

The Office for Nuclear Regulation, ONR, has identified AWE Aldermaston as one of just seven out of 36 nuclear sites in the UK which will require an “enhanced level of regulatory attention” over the coming year.

The annual report by ONR states that AWE Aldermaston is currently under investigation for two apparent breaches of the law: a failure to comply with instructions for radioactive waste management and for allowing “shortfalls” to arise in the operability and availability of fire detection systems at the site.

It adds that the site requires additional attention because it houses a range of ageing facilities and because of concerns about “the timeliness and quality of periodic reviews” and notes that a number of safety cases for the site “do not meet expectations”.

It also highlights the additional regulatory effort needed to manage the major building programme currently underway at Aldermaston to enable the factory to manufacture new nuclear weapons.

However, the regulator states that it is satisfied that there are “no immediate safety concerns” at the Aldermaston site, and that as the AWE Burghfield site is less complex than the Aldermaston site, it should receive a “routine” level of regulatory attention.

AWE Aldermaston was first listed as an enforcement priority by the nuclear safety watchdog last year, following the discovery of corrosion in structural steelwork in a building which manufactures enriched uranium components for nuclear warheads and fuel for nuclear submarines.

Pete Wilkinson, director of the Reading-based Nuclear Information Service said: “The Office for Nuclear Regulation's report shows that, while safety standards at many nuclear sites are improving, AWE is just muddling along and marking time.

“Vast sums of money are being spent at Aldermaston but we are seeing no improvement in standards because the money is being spent on experiments and facilities to build new nuclear weapons, rather than on improving safety.”

A statement from AWE said: “Delivering safe and secure operations is a core priority for AWE and it fully supports the ONR’s focus on continuous improvement, effective hazard control and maintaining high standards.”