AN American engineering group is set to buy the government’s one-third stake in the Atomic Weapons Establishment (AWE), the Berkshire complex that manufactures and maintains the warheads on Britain’s nuclear missiles.

Jacobs, an engineering company headquartered in Pasadena, California, is tipped to win a long-running auction for the stake, which was put up for sale last year after ministers decided to break up British Nuclear Fuels, a state-owned agency that included the AWE holdings among its assets.

Jacobs, which employs 54,000 people worldwide, has been in a run-off with another American engineer, Fluor Corporation, since January. The winner is expected to be announced in a few weeks’ time.

Industry sources said last week that Jacobs was the likely winner, pointing to its recent success in securing large and lengthy contracts at AWE.

“Everyone believes Jacobs has got it,” said a senior defence-industry executive. The stake is thought to be worth more than £100m.

Selection of the Californian company is likely to reignite a long-running controversy about the independence of the UK’s nuclear deterrent.

It would mean that two-thirds of the shares in AWE are owned by American groups. One-third of the company is already owned by Lockheed Martin, the leading American defence contractor, with the remaining third in the hands of Serco, the British support-services group.

AWE traces its roots back to the start of the UK’s independent nuclear-weapons programme after the second world war.

In 1949 a former Royal Air Force base near the Berkshire village of Aldermaston was chosen as the site for atomic-weapons research and manufacture. AWE has since expanded to another nearby site at Burghfield.

The management and day-to-day operations of the site were handed to private contractors in 1993. The current contractor, AWE Management, has three shareholders - BNFL, Lockheed and Serco - and has a deal to run the site until 2025. The Ministry of Defence holds a golden share. AWE has around 4,500 directly employed staff and another 2,000 contractor staff.

The Aldermaston site has become a focal point for protesters against nuclear weapons. In 1958, 10,000 people joined the first “ban the bomb” march from London to Aldermaston.

While the bulk of AWE’s work has been in maintaining the current fleet of the American-designed Trident missiles that are carried by Royal Navy submarines, the company is likely to be heavily involved in the development of a new generation of nuclear weapons.

Last year the government announced that it would replace the ageing Trident weapons and submarines at an estimated cost of £15 billion£20 billion over the next 30 years.

Investment bank NM Rothschild has been handling the auction for the government alongside the Shareholder Executive, an arm of the Department for Business, Enterprise and Regulatory Reform that administers the state’s stake in commercial groups.

The two other shareholders, Lockheed and Serco, did have preemptive rights to buy the government stake when it came up for sale but have chosen not to exercise them. Amec, the British engineering group, examined a bid but later withdrew.

In March AWE awarded Jacobs a six-year contract to provide engineering support at Aldermaston and Burghfield.

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