The heat wave in Europe disrupted flights in the UK due to a radar issue and some severe thunderstorms.
The UK's main air navigation service said it was dealing with a technical problem with a system at an air traffic control center in Swanwick, southern England, which was causing the flight restrictions. Heathrow and Gatwick, the UK's first and second busiest airports, had been experiencing limitations to their operations. Heathrow saw a record-breaking 37.9 Celsius (100 degrees Fahrenheit) twodays ago. Stansted and Luton airports said their services were unaffected. Rail services also suffered extensive delays due to the heat wave in the UK. Speed restrictions were introduced to prevent the lines from buckling.
Thursday was the hottest July day on record and the UK's second hottest day. Friday however has been cooler than Thursday, with temperatures ranging from 23C to 25C in most areas (73F to 77F), rising to 27C in south-east England. The UK's air traffic controller said in the afternoon it had "fixed the issue sufficiently to safely increase traffic flow rates and will see an improving picture through the rest of the day". Anthony Smith, chief executive of independent watchdog Transport Focus, said: "All passengers told not to travel due to extreme weather should be entitled to claim compensation."