The National Grid Electricity System Operator said in October it was “unlikely” that households and businesses might be deprived of power for short periods to prevent a collapse.
But Mr Dowden, the Chancellor of the Duchy of Lancaster, said on Sunday people could be confident that there would not be blackouts this winter, save for “some very, very major external shock that would affect the supply of power into this country”.
He said he had engaged with Business and Energy Secretary Grant Shapps on the issue “a lot”.
“It is the case that excepting some very, very extreme, unforeseen scenario disrupting supply, we would not expect [cuts] to happen, no, so people can have that confidence,” Mr Dowden told Times Radio.
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Concerns over Britain’s power supply increased last month when the ESO issued and then rapidly cancelled a notice that warned of tight margins between supply and demand.
Planned blackouts hit the UK during the 1970s in response to the miners’ strikes and the oil crisis.
There have also been major unplanned cuts during storms, including in 1987 when more than 1.5 million people were left in the dark.
But the lights will stay on this winter unless the gas-fired power plants that produced 43 per cent of Britain’s electricity over the past year cannot get enough fuel to keep running.