Heavy fog expected to cause rush hour delays
Dense fog is expected to cause travel disruption to flights in some parts of the UK today.
Heathrow airport said around 45 flights, 10% of its departures, had been "pre-cancelled" as a yellow weather warning for fog covers much of England and east Wales.
After long delays on Sunday and the cancellation of 50 flights some passengers landed at Britain's busiest airport in the early hours of the morning, but many hoping to take off today will be disappointed.
A spokeswoman for Heathrow airport said: "We've got extra passenger ambassadors in the terminals to provide assistance for those travelling today. Once again we would like to apologise for the disruption."
Passengers are advised to check with their airline for updates.
Those hoping to travel through Gatwick have also been advised to check ahead for any disruption.
Meanwhile five flights have been cancelled at Manchester Airport.
Leeds Bradford, Birmingham and Liverpool Airport also said there could be some disruption to flights.
The Met Office weather warning is valid until midday, with fog expected to slowly clear throughout the morning.
The forecaster said the fog would become widespread and dense overnight into Monday and warned: "Travel may be impacted by poor visibility, with some minor disruption expected."
Visibility could be reduced to less than 100 yards, it added.
Motorists have also been advised to take care on the roads amid the thick fog with Highways England urging people to allow extra time for any journeys.
The agency said on its website: "Road users will need plenty of extra time to do their usual commute, especially as the fog is expected to lift very slowly during the morning."