British Energy provoked protest from safety campaigners yesterday by announcing plans to extend the lives of two of its oldest British nuclear power stations — Hinkley Point B and Hunterston B — by five years, until 2016.

Bill Coley, its chief executive, said that the two reactors, which a year ago were forced to close because of cracks found in boilers, could be kept running for a further ten years beyond that, until 2026.

Construction of the stations at Hinkley Point, near Bridgwater, Somerset, and Hunterston in North Ayrshire, Scotland, began in the 1960s. The advanced gas-cooled reactors, which together generate about 5 per cent of the UK’s electricity needs, entered service in 1976 and were due to be retired in 2011.

However, Mr Coley said that a technical and economic reevaluation of the plants had led to authorisation being granted to continue operating them for at least five extra years.

The announcement dismayed environmental groups. Ben Ayliffe, nuclear campaigner at Greenpeace, described the decision as “completely ludicrous”. He said that British Energy, which generates around a fifth of the country’s electricity, has faced a string of technical problems with its ageing fleet of eight nuclear power stations, some of which date back to 1965.

Mr Coley, however, dismissed any safety concerns. “If there were any safety issues whatsoever, I would shut them down straight away,” he said, adding that British Energy planned to invest £90 million overhauling the two reactors over the next three years, including upgrading boilers and transformers.

He added that there were similar plans to extend the lives of two other nuclear power stations, at Hartlepool and Heysham, which are due to be decommissioned in 2014. A decision on these will be taken in 2011.

Hinkley Point B and Hunterston B have been subject to outages and load restrictions in recent months related to the boiler cracks.

Hinkley Point is generating only around 420 MWh, roughly 70 per cent of full power.

At the time of the outages, Mr Coley said that these had been caused not by human error but by the age of the plants and the strain of operating at high temperatures.

Mr Coley denied that the life extensions would ease the pressure on the Government to develop new nuclear power stations. “This does not obviate the need for new generating capacity of all types in the UK,” he said.

In November, British Energy said that costs associated with the problems at its power stations were expected to run to at least £50 million.

As well as cracks in the graphite brick cores of the ageing reactors at Hinkley and Hunterston, corrosion was also discovered on wires in two reactors at its 35-year-old Heysham 1 and Hartlepool plants. These two sites, which are capable of supplying power to 1.5 million homes, have been out of action ever since. It remains unclear when they will reopen.

The proposed life extension of the Hinkley and Hunterston plants precedes an announcement by the Government on its commitment to a new generation of nuclear power stations, expected early next year.

The existing British stations are reaching the end of their lifetimes and by 2023 all but one, Sizewell B, are due to be shut.

If it does support nuclear power, the Government will join countries including China, India, Russia and the United States in pressing ahead with ambitious nuclear programmes, as the world seeks to wean itself off fossil fuels linked to climate change.

Times Recommends

• Millions enter fuel poverty as energy costs soar
• High street sales stage surprise July upturn
• Persimmon says housing market will not worsen