FEARS over structural safety have halted production work in an AWE Aldermaston building.

Work has stopped in one of the main manufacturing facilities at the nuclear weapons establishment because of safety fears caused by corrosion of structural steelwork.

The Office for Nuclear Regulation, ONR, has issued managers at AWE with a formal improvement notice ordering the factory's managers to halt all non-essential operations in the building while the extent of the corrosion is investigated.

The problem came to light following a routine inspection at the building, thought to be the A45 facility, one of the older manufacturing facilities at the Aldermaston site.

After further inspections routine operations in the building were stopped.

AWE must complete a programme of remediation work before normal operations can begin again. It is not known how long this will take.

Although the corrosion was discovered in August 2012, details of the problems only emerged in a report on the AWE site which was published on the ONR website a few days ago.

Green Party MP Caroline Lucas said “I am glad that the Office for Nuclear Regulation has acted promptly to protect the public from any safety risks that could arise from the current problems at Aldermaston, but some serious questions remain over the adequacy of structural inspections conducted in the past.”

Peter Burt of the Nuclear Information Service said “We should be concerned that AWE apparently tried to hush these safety problems up and that the matter only became known to the public when ONR insisted on reporting details in one of its regular reports on the site”.

A spokesperson for AWE said: “AWE is working closely with the ONR to ensure that its inspections, safety measures and planning for remedial work are carried out with their full knowledge and consent.”