Flight delays and cancellations occurred at London Stansted Airport after lightning struck the aircraft's fuel supply system during storms, during which more than 64.000 lightning strikes.
The British sky was illuminated overnight by electric storms and there were reports of flooding and homes being left without electricity after torrential rains.
Stansted is London's third busiest airport and a major hub for Ryanair, which has announced that its customers can be fully reimbursed.
"Unfortunately flights were canceled this morning at Stansted Airport due to a breakdown in the airport's fuel supply system due to lightning," a spokesman said.
The catering system was repaired this morning, but travelers were warned to contact the airport before traveling, and passengers stranded on airplanes for hours protested on Twitter that no explanation had been given for the delay.
"Engineers have now repaired the system. "However, flights may be delayed or canceled," Stansted Airport said in a statement.