It was announced on Monday morning that the Demand Flexibility Service (DFS), which is designed to avoid blackouts, may have been brought in for the first time to reduce expected strain on the electricity grid.

The scheme sees households, which are signed up for the initiative, paid to not use things like electric ovens, dishwashers and tumble dryers between certain hours.

It is the first line of defence in the event that peak evening demand exceeds supply over the coming winter.

The DFS has been tested twice.

The UK's power grid usually relies on imports from France over the winter months to make up any shortfalls in electricity output.

However, the French nuclear power industry, which accounts for around 75% of its usual electricity generation, is in turmoil.

More than half of the reactors run by state energy firm EDF have been closed due to maintenance and technical problems.

It is exacerbating the wider energy crisis across Europe as countries face down the colder months.

That is because the continent is without the usual volumes of gas flows from Russia because of Moscow's war in Ukraine.

Octopus Energy is by far the most active energy supplier in the DFS.

It has previously released data showing that its customers had helped reduce demand by more than 100 megawatts during both tests.

Other options available to National Grid for power rationing include asking non-critical factories to shut down.

In the most severe circumstances, planned three-hour rolling blackouts could be imposed if gas-fired power came under pressure and other means of generation failed to make up the balance.

National Grid's Electricity System Operator (ESO) said last month that such a scenario was "unlikely".

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Its latest report on the UK's readiness showed, under a base case scenario, that margins between peak demand and power supply were expected to be sufficient, and similar to winters of recent years thanks to secure North Sea gas supplies, imports via Norway and by ship.