National Grid winter capacity is lowest in a decade

The grid says electricity margins will be 'tight but manageable' and has asked companiesto be ready to cut output at peak times

National Grid has said it is more likely to draw on additional sources of power to keep the country's electricity running after the chance of blackouts rose to its highest in a decade.

The operator of pipes and pylons said it had enlisted power stations to provide extra capacity and asked companies to be ready to reduce usage to help it meet peak demand.