Over 100 flights have been cancelled due to dense fog at Heathrow and also London City Airport and the Met Office says conditions may persist today.
Passengers are advised to check the airports’ and airlines’ websites before flying. A Met Office spokesman said: "We have seen quite dense fog in the south east and east of England today and over night we expect that to become more widespread, with visibility reduced to 50 metres. Tomorrow fog will take a while to shift in London, the south east and the east of England up to York, and will only become less widespread in the late morning."
By 6.30am a total of 21 flights from Heathrow were already cancelled. Destinations affected included Manchester, Glasgow, Amsterdam, Brussels, Stockholm, Cologne and Nice.
A Heathrow spokesman said: "Passengers are being re-booked or put up in accommodation by airlines, while some domestic passengers are being taken in coaches to their destination. Some delays to flights are also occurring so we advise passengers to check with their airlines before travelling."
At London City airport, ten morning flights were grounded, affecting services to Dublin, Rotterdam and Paris among those hit. The website is currently showing cancellations and delays.
Gatwick airport said it was experiencing low visibility but it had caused no disruption to flights, and Stansted airport which is technically in Essex, about 30 mins north by train from central London, said it was "business as usual".