Forecast thunderstorms today have triggered British Airways flight cancellations and delays across three London airports.

Restrictions have been imposed by National Air Traffic Services for safety reasons on the number of aircraft which can land and take-off each hour at Heathrow, Gatwick and London City, according to the airline.

“As a result it has been agreed between Heathrow airport, Nats and airlines to proactively reduce the flight schedules at Heathrow to ease congestion,” BA said in an alert on its website.

“These restrictions combined with aircraft being re-routed to avoid the areas of severe weather will lead to delays on some flights and a number of short-haul cancellations.

“We are sorry for the difficulties caused by the poor weather and are doing all we can to minimise the effect it has on our operations.”

Passengers due to fly today are being urged to check the latest information about their flight before travelling to the airport.

“If your flight has been cancelled, please do not travel to the airport,” BA said. “We have a policy in place outlining the options available to you and how to make changes to your booking.”