The head of energy giant Shell has warned that energy rationing in Europe cannot be ruled out because of concerns about gas supplies from Russia, the BBC reported.

Speaking at an energy conference, Ben van Beurden said Europe would face a really harsh winter"and energy prices would rise significantly.

"Some countries will fare better than others but we will all be facing a very significant escalation in energy prices."

The EU is heavily dependent on Russian fossil fuels, with Russia supplying 40% of its natural gas. It also supplies 27% of the EU's oil imports.

The EU has taken steps to phase out Russian fossil fuels in response to the war in Ukraine by banning most oil imports by the end of 2022. It has pledged to cut gas imports, but agreeing on further measures, such as a total ban, has proved more difficult.

Member states are trying to stockpile gas over the summer in anticipation of increased demand for the fuel in winter, but recent moves by Russia to cut supplies have heightened fears that the continent may struggle to build sufficient supplies.

Europe's gas reserves are 62.6 per cent full and there are fears that reaching the target of at least 80 per cent by winter will be difficult.

The UK imports less than 5 per cent of its natural gas from Russia, but a third of its supply depends on Norway.

There are fears that if Russia continues to reduce supplies to the European Union or the bloc boycotts gas purchases, competition for supplies will intensify.

So while the UK would not be as badly affected by supply disruptions as the EU, it would be affected by rising prices on world markets as demand increases.

Earlier this week, the head of UK energy watchdog Ofgem warned that electricity bills will rise faster this winter than previously forecast.

One industry analyst predicted a rise in UK domestic bills of more than £1,200 a year in October. Cornwall Insight reported that the typical domestic customer is likely to pay £3,244 a year from October and then £3,363 a year from January.

The government is in talks with energy company Centrica to reopen the giant gas storage facility in case supplies to Europe from Russia are cut off.