Leaked documents have revealed what the Government would do if homes are plunged into darkness this winter.
Unrelated to the power cuts described by the National Grid, which warned of planned three-hour outages this winter, Programme Yarrow deals with "severe" emergency disruption.
The confidential plan by the Government sets forth how the country would cope with blackouts for up to a week. The blueprint was created back in 2021 before Russia's invasion of Ukraine put a strain on UK gas supplies.
The plans warn that all sectors, including transport, food and water supply, communications and energy could be "severely disrupted" for as long as a week during the blackouts, according to documents obtained by the Guardian.
It comes amid a separate warning of planned blackouts on "really cold evenings" by the National Grid. The outages have been described as a "worst case scenario" by the supplier's CEO John Pettigrew, the Mirror reported.
With that in mind, here's what it could mean for UK households if emergency blackouts were to happen.
Food transported to the most vulnerable
The plans suggest there will be a huge focus on getting food, water and shelter to the most vulnerable people. This includes the elderly, young people and carers.
A series of tests with Government departments and councils all over the UK are reported to have taken place over the past few days to stress-test the process.
The type of technical fault that could lead to these measures being launched include flood damage or a lightning strike on a substation, as well as an attack by a hostile state on power cables under the sea.
Emergency broadcasts on Radio 2 and Radio 4
In the worst-case scenario, only analogue FM radios would work, with just BBC Radio 2 and 4 broadcasting.
The BBC has reportedly already prepared scripts for presenters to read on-air, if a shortage of energy causes blackouts this winter. This is because local radio stations will only have a couple of hours of back-up generator cover.
Programme Yarrow was designed for situations where power is unavailable, without no warning, to all areas without backup generators over the colder months.
The plans suggest 60 per cent of electricity demand will be met "between day two and day seven" - when households and businesses will be given "intermittent access" to make sure supplies don't run out.
An agreement between energy regulator Ofgem and National Grid states 100 per cent of the electricity demand should be restored after one week.
Three-hour blackouts
In the most severe situations, UK homes could be faced with three-hour planned blackouts between 4pm and 7pm.
If necessary, it's likely they will happen in January and February next year "on those weekdays when it's really, really cold". People will be given 24 hours' notice before the blackouts begin.
The plan, which is designed to cut power evenly across the country, could be published up to a week ahead on a rolling basis to allow people to make any arrangements they need.
National Grid has also composed an incentive strategy, which could come in this month, and will pay companies and households to reduce their demand during times of low supply.
A Government spokesperson told the Mirror: "As a responsible government, it is right that we plan for all potential scenarios and work with the industry to prepare and exercise robust contingency plans.
"This work is ongoing continuously and is an important strand of our national resilience planning.
"Local and national exercises are a part of this ongoing work and ensure we are able to effectively respond to any wide range of scenarios, no matter how unlikely they may be."
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