LONDON, May 21 (Xinhua) -- The worst British airports for flight punctuality was revealed on Monday, with passengers departing from London Luton Airport facing the longest flight delays in the country.

Planes left Luton took off 19.7 minutes late on average, with Gatwick, Jersey and Durham Tees Valley next worst, according to the data from the British Civil Aviation Authority (CAA).

The data showed that Gatwick's average take-off delay in 2017 was next worse 18.9-minute delay, followed by Jersey Airport, at 18.7 minutes.

The top performers were Heathrow -- flights were 11 minutes late -- Leeds Bradford, Belfast City and London City.

Scheduled and charter flights, but not cancelled services, from the 25 busiest airports were examined in the study.

Passengers can claim compensation when flights are delayed by more than three hours unless there are "extraordinary circumstances," such as severe weather or security alert.

Payout range from 219 pounds, about 294 U.S. dollars, to 524 pounds, or 703 U.S. dollars, depending on the length of the flight and how long it was delayed, reports said.

A CAA spokesperson said the data will enable passengers to "make informed choices about which airports they fly from," and that the industry "should constantly strive to improve punctuality to enhance the passenger experience."

A spokesperson for London Luton said the airport "regrets any delay our passengers experience," adding that punctuality was influenced by "many factors" outside its control including air traffic control strikes, late-arriving aircraft, bad weather and congested airspace.

Meanwhile, London Gatwick Airport said it is doing "everything within its power" to improve its punctuality.