Russia rescued British energy consumers by ensuring a steady flow of gas into the power network as supplies from Norway faltered during the cold weather, industry customers users said today.

As the National Grid warned of a "high" possibility of shortages in the north-east and south-west owing to another cold snap, the Major Energy Users' Council said Britain had been lucky to survive without shortages. Eddie Proffitt, chairman of the council's gas group, said: "The [British] gas industry has coped very well but we have been lucky. It would have been desperate if we had seen the kind of disputes between Russia and Ukraine that have reduced gas flows on the continent in the past two or three Januaries."

Politicians said four "gas balancing alerts" – warnings of pending shortages – in the space of a week meant it was time Britain reviewed its whole energy policy.

"This winter has shown the system we have devised does not have the resilience it should have. It runs on a 'just-in-time' principle which has economic benefits when it works but risks ending up in a 'just-too-late' if all goes wrong," said John Hemming, MP for Birmingham Yardley.

"If the Russians had hit the kind of problems with its neighbours seen in previous years then we would have toppled off the knife edge we have been sitting on with our gas supplies."

The disruptions to supplies from Norway – normally seen as highly reliable – left Britain importing gas through the interconnector pipeline which runs from Zeebrugge in Belgium to Bacton in north Norfolk. In previous years shortages from Siberia have led German and Dutch suppliers to halt gas exports to Britain.

The National Grid admitted that much of the stress in the gas supply system had been caused by technical problems on Norwegian fields such as Ormen Lange and Troll but said everything was back to normal. A Grid spokeswoman insisted the gas alerts had worked as they were expected to: drawing new supplies from other sources, such as liquefied natural gas on board vessels and the continent. She declined to comment on what would have happened if Russian gas had not been flowing normally.

The Major Energy Users' Council also had serious concerns that changes to the regulatory regime next year could make the situation worse. Proffitt said there were 1,250 customers around Britain on "interruptible" gas contracts, but this number would fall to 27 by October 2011 when new Ofgem regulations come into force. "Some of our members are very concerned about this because they fear a supply shortage could lead to demands that sites lose their gas. Many of those who choose to have interruptible contracts have back-up power sources such as diesel-fired generators," he said.

Nearly 100 customers had their power cut at one stage last week, including the Vauxhall car plant at Ellesmere Port on Merseyside. National Grid said none were cut off today though its website earlier in the day had said that there was a high risk of interruptions in the north-east and south-west. This eased off later.