LONDON (AP) — British meteorologists say up to 20,000 lightning strikes hit the U.K. during a powerful overnight thunderstorm, and a London-area airport is reporting flight disruptions after an aircraft refueling system was damaged.

London Stansted Airport said Sunday that a lightning strike had rendered the fueling system "unavailable for a period this morning. Engineers have been on site and have now restored the system, however flights may still be subject to diversion, delay or cancellation."

Britain is in the middle of a long holiday weekend, and budget airline Ryanair couldn't say how many of its flights had been affected at the airport, but was offering full refunds to some.

Meteorologist Charlie Powell said information suggested there were "somewhere between 15,000 and 20,000 strikes across the U.K. during the overnight period."