"We experienced issues with two power generators causing loss of power in selected UK areas. The issue is now resolved and the system has returned to normal. Anyone continuing to experience a local issue should contact their local Distribution Network Operator for assistance," ESO said on Twitter.
Local media reported that the power cut had affected homes and transport system, with trains being delayed and cancelled across England and Wales.
According to the BBC, Gatwick, Heathrow and Luton airports had not been affected by the power outage.