The National Grid's "base case" is there will be sufficient energy to provide usual electricity levels this winter. But it has modelled two more worrying scenarios – the first of which sees electricity imports cease via interconnectors from France, Belgium and the Netherlands, but with gas still flowing through the 725-mile Langeled undersea pipeline from Norway to the Yorkshire coast. Having struck deals with three power companies to keep additional coal-fired power generators on standby, National Grid says under this scenario, supply interruptions will be avoided – as long as energy use by households and businesses is managed, with some shifting to different times of the day. Yet a second, much more serious scenario, sees the energy crisis across Europe escalate, with diminishing supplies across Britain then limiting use of our gas-fired power stations. Distributors would then be forced to cut off electricity to homes and firms for up to three hours during the day, say the National Grid.