UK warned it could face power outages for three hours a day this winter

EU countries have already agreed to reduce gas consumption by 10 percent and electricity by 15 percent to avoid potential continental power cuts this winter. On Thursday, the German ambassador in London appeared to suggest that Britain should join the attack.

Miguel Berger told the BBC: “Half of France’s nuclear power stations are down, and that means, and I think the UK is one of the electricity importers in the winter, there may be electricity shortages.

“So I think measures like, for example, reducing gas consumption, reducing electricity consumptionare very important signals to be given to the population.”

But leading sources in Germany insisted that Berlin felt there was no point in telling Britain how to handle its potential energy crisis.

Mrs. Truss has said before that she wouldn’t be telling people to ration their energy consumption this winter. On Thursday, sources in Downing Street ruled out following Brussels’ lead, claiming the situation in the UK was “quite different” from that in the EU.

A progressive blackout plan, which has not been used since the 1970s, would require the approval of the government and the king.

Britain may need to import energy from Europe

Ms Truss agreed to rejoin an EU-backed energy pact between the bloc’s North Sea countries as she sought to bolster the country’s supplies before winter.

She also agreed to make plans with Emmanuel Macron for the UK and France to build more nuclear power plants – and urged the EU and Norway to continue to supply Britain with electricity and gas as they run their own risk of power outages.

The prime minister was urged to launch public information campaigns warning the public to save energy by turning down the thermostat and taking showers instead of baths.

Professor David Halpern, of the controversial Behavioral Insights Team – known as the “nudge unit” – said households should be warned that heating a room costs eight times more than using an electric blanket and 40 times more than a hot water bottle.