Energy blackouts this winter would pose a serious risk to vulnerable people who rely on medical equipment, a former senior government adviser has warned.
On Thursday, the National Grid said customers could be left for periods of time without energy this winter due to gas shortages as Russia's invasion of Ukraine continues to disrupt supplies to Europe.
“In the unlikely event we were in this situation, it would mean that some customers could be without power for pre-defined periods during a day, generally this is assumed to be for three-hour blocks," the National Grid said.
Despite the warning, the government has said it is "confident" the UK's energy supplies will "protect households and businesses in all scenarios".
However, experts have criticised the government's position, warning that a failure to encourage the public to use less energy will make shortages worse and could put vulnerable lives at risk.
Adam Bell, former head of energy strategy at the Department for Business, Energy & Industrial Strategy, told Yahoo News UK blackouts could leave Brits who rely on medical equipment at home - such as CPAP machines that help those with breathing difficulties - without power.
“The system operator and the regulator has to look after vulnerable people this winter," said Bell.
"The problem is, is that they don’t know who all these people are - and physically making sure they’re all okay is extremely challenging.
"You can’t switch off power to people’s houses remotely, you have to switch off entire areas at once, and that could impact some vulnerable people, people who may rely on, say, a CPAP machine - or similar sorts of machines to support their health."
He added: "I don’t want to scaremonger, but people should be alert to the fact that the more they can do to reduce their use, the more they can help stave off these risks.”
Simon Francis, co-ordinator of the End Fuel Poverty Coalition, told Yahoo News UK it is vital that there is enough energy supply for vulnerable and disabled people this winter and urged the government to guarantee the supply.
"People such as the disabled and elderly, can't just turn off their energy use," he said. "They are already in fuel poverty and keeping usage to a minimum, so it will be life threatening in some situations."
Liz Truss appears to have rejected these concerns, insisting that the UK has “good energy supplies” and “can get through the winter”.
It is also in keeping with Truss's pledge during the Tory leadership campaign to rule out energy rationing this winter.
There are wider concerns that an unintended consequence of the government's energy bill support package could be that households make less of an effort to use less energy.
"[This policy] could push us to energy rationing later in the year because there's no incentive for people to reduce their energy usage," John Macdonald, director of strategy at the Adam Smith Institute, told Times Radio last month.
Watch: Energy crisis: How worried should I be about the lights going out?