Wholesale gas prices in Britain jumped by nearly 15 per cent yesterday after a leak from a North Sea pipeline triggered concerns about possible supply problems this winter.

StatoilHydro, the Norwegian oil group, said that it had discovered the leak from a gas pipeline linking its Kvitebjoern field in the North Sea to the Kollsnes onshore processing plant.

The state-controlled company said that the pipeline, which pumps an estimated 5 per cent of Norway's total gas output, was likely to be out of action until next spring.

“It will be shut down until we get it repaired and that is currently set for spring 2009, unless we manage to push this forward,” a spokeswoman said.

Statoil was forced to close the Kvitebjoern field, a move that reduced gas supplies to the UK from Norway via the Langeled pipeline by 18 per cent to 40 million cubic metres a day.

The news sent the forward price of gas for delivery to Britain this winter 14.6 per cent higher to 104p per therm from 90p as traders fretted about the increased threat of supply problems. Prices for immediate delivery also rose from 55p to 58p per therm.

Statoil said that it was trying to work out how to stop gas escaping from the pipeline.

Damien Cox, energy analyst for John Hall Associates, said: “Consumers really could have done without this. It's not a serious supply issue right now because demand in August is low, but it does raise the likelihood of problems this winter.”

The depletion of gas supplies from the British section of the North Sea means that the UK is increasingly reliant on imported gas. The Langeled pipeline is a key supply route.

About 40 per cent of the gas used in Britain this year will be imported, up from 27 per cent in 2007. That proportion is expected to rise to 75 per cent by 2015.

Britain is highly exposed to supply disruptions because it lacks adequate gas storage, with a capacity of only 13 days compared with 99 days in Germany and 122 days in France.

David Hunter, an analyst from McKinnon & Clarke, the energy consultancy, said: “Gas available to export from Norway to countries including the UK will be cut significantly and, without adequate storage, the UK will be left to negotiate with Russia and the Far East for supplies or risk running low on energy.

“The Government's inability to make long-term energy security decisions over the last decade is coming home to roost. Since the 'dash for gas' in the 1990s, the lack of political will to make tough decisions has left Britain short of power. Our dependence on international supplies leaves the UK extremely vulnerable.”

The rise in gas prices has affected the cost of electricity because 40 per cent of British electricity is generated by gas-fired power stations.

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