Households have been feeling the pinch of rising energy costs, with domestic fuel bills nearly doubling in the last three years.

But residents struggling to keep their homes warm would have been forgiven for pinching themselves yesterday as natural gas was given away - for nothing.

The bizarre development, as the nation is supposedly gripped by an energy crisis, came on the wholesale market with some traders even paying up to 5p a therm to sell their supplies, after the UK market was flooded by fresh imports from Norway.

Gas sold for use yesterday fell into "negative territory" because of the over-supply through the new Langeled pipeline, which opened on Sunday and delivers gas from the Norwegian North Sea to Easington in East Yorkshire, and warm weather in the UK which dampened demand.

National Grid said it was the first time it had seen traders have to pay to sell gas on a national scale.

But households hoping for lower bills as a result were left disappointed when industry experts warned wholesale prices for the middle of winter were still high.

Gas for the domestic user has nearly doubled since 2003, electricity has gone up 60 per cent and the average combined bill for both is now more than £1,000-a-year.

Karen Darby, chief executive of price comparison and switching service, said: "We appreciate that energy companies have to forward buy their supply, however, we urge Ofgem to ensure that provisions are put in place to make sure households profit from falling wholesale prices.

"Consumers are always the first to feel the pinch when prices go up and they will fail to see why they can't benefit from reduced wholesale prices. It is a very competitive market and once one provider passes these savings back to the customer, others will quickly follow."

That, however, is unlikely to happen in the forseeable future.

Russell Hamblin-Boone, of the Energy Retail Association, said the surplus in the system was an "anomaly", while Chris Lock, a spokesman for energy regulator Ofgem, warned: "Once people start to put on their central heating it will increase demand for gas a lot."

Langeled is one of a number of projects aimed at boosting supply to the UK now that it is a net importer of gas.

Last winter restrictions to supplies from Europe sent the cost of wholesale gas to as high as about 250p a therm as demand overtook supply.

Price reporting agency Platts yesterday said gas for use in January and February was still trading at more than 70p a therm - well above the 60p average level of last winter.

Industry experts said long term contract prices were more relevant to household energy bills than short term day trading prices, which are more volatile as witnessed yesterday.

It is hoped within the industry, however, that prices will eventually start to fall, leading to calls for lower energy bills from next year.