THE UK Government is testing emergency plans to deal with blackouts lasting up to seven days in the event of a power outage, according to a report. 

The Guardian reports it has seen documents which warn that in a “reasonable worst-case scenario” all sectors, from transport to food and water supply, could be “severely disrupted” for up to a week. 

This comes amid growing fears over the security of supply this winter with the National Grid previously warning of households losing power for up to three hours at a time if gas supplies run low. 

The newspaper reports that the documents showed ministers will make it a priority to get food, water and shelter to young and elderly people as well as those with caring responsibilities. 

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The Met Office has also warned that Britain is facing a higher risk of a cold winter. 

Whitehall officials are currently stress-testing Programme Yarrow, the confidential plan for a power outage, and have held a series of exercises with various departments and councils across the country in recent days. 

The cross-government blueprint was first created in 2021, prior to Russia’s invasion of Ukraine in a bid to improve resilience in the event of a major technical fault on the National Grid. 

It is not specifically related to the National Grid’s warning of blackouts. 

The type of technical fault envisaged by government planners includes food damage or a lightning strike on a substation but could also cover an attack by a hostile state. 

In the worst-case scenario outlined by the plan, only analogue FM radios would work, with only BBC Radio 2 and 4 broadcasting. 

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A source told The Guardian: “The government doesn’t want any publicity on Yarrow, as they don’t want it to be seen as linked to Ukraine, energy supply and the cost of living. 

“But we need to think about how we can help people in advance. The fact they’re talking about it now means they have a real concern it could happen.”

Cabinet Office sources also told the paper they did not recognise this claim, as planning was unrelated to events in Ukraine. 

Programme Yarrow prepares for a situation in which power is unavailable, without any pre-warning, to all premises without backup generators during winter. 

It is aimed at a situation more severe than what was outlined by National Grid last month. 

A government spokesperson said: “As a responsible government, it is right that we plan for all potential scenarios and work with 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 of a wide range of scenarios, no matter how unlikely they may be."