The UK's grid operator has asked three reserve coal units to be ready to supply power and consumers to curb demand on Tuesday, as it tries for a second consecutive day to plug the gap left by a dearth of wind generation.

He added that the method may be quick and dirty, but it is much more likely to pass than it was five years ago.

France is increasing the availability of its state-owned fleet of nuclear reactors after months of extended outages, in a sign of relief for Europe as it battles a historic energy crisis.