UK energy regulator Ofgem on Thursday urged consumers to cut their usage with winter approaching, although the government is downplaying any threat to electricity supplies over the cold period.
The call comes a week after Prime Minister Liz Truss ruled out an official government energy-saving campaign to encourage less consumption this winter.
"All of us should be thinking about how to reduce our energy use where possible," Ofgem chief executive Jonathan Brearley said in a speech published on the regulator's website.
"This is not only the most direct way to reduce our bills. It directly helps with security of supply, contributes to decarbonisation, and saves money for the public finances," he added.
Wholesale gas and electricity costs are at an all-time high, he pointed out, "hitting families and businesses."
Despite massive government subsidies to cap electricity bills, households still face bills twice as high as last year, he said.
"And we are heading into winter, in the middle of a major European land war where Russia is using gas as a geopolitical weapon," he warned.
The UK's National Grid operator ESO has also introduced financial incentives to reduce consumption at key times.
In contrast, the government recently said it was not sending Britons any instructions on saving energy, and has downplayed fears of energy blackouts this winter.
Climate Minister Graham Stuart told London radio station LBC last week: "We're... hesitant to tell people what they should do when we're not a nanny-state government."
Elsewhere in Europe, governments are encouraging energy saving in the face of soaring gas and electricity prices and supply risks, and are implementing measures to reduce consumption in government offices and public buildings.
Brearley also played down the potential risk of power cuts in the UK.
A National Grid report earlier this month warned that in an extreme scenario of a halt to gas imports from Europe, combined with insufficient local production, power cuts of several hours could be implemented.
"I understand why the media coverage has concentrated on the worse-case scenario preparations. So to be clear, we do not think a supply emergency is likely," he said.
He repeated the government's view that the overall picture for the UK "remains favourable" and that it is in "a stronger position than many European countries" as it is less dependent on Russian gas.
However, he admitted that it was likely to be "another challenging winter".
