A number of flights at airports in London have been cancelled as thick fog shrouds the capital on Monday morning.

Flights at Heathrow and London City have been disrupted as forecasters warned foggy conditions could reduce visibility to 50 metres or less.

A yellow weather warning, which covers London and most of the South East, is in place until 11am, and the Met Office has warned of difficult travel conditions on Monday morning.

By 6.30am, seven flights from Heathrow and three from London City were cancelled.

Niamh Murray, Met Office operational meteorologist, said current weather conditions are the “perfect recipe” for fog.

“With autumn and winter and getting fog during this time of year, we get much longer nights, and that allows temperatures to fall away,” she told the Press Association.

“We get a longer period of cooling and also the temperatures are much lower, so they’re much closer to the temperature that we need for the air to become saturated and therefore form fog.

“Another thing that we need to form fog is quite light winds, not absolutely no winds.

“We just have the perfect recipe at the moment: light winds, clear skies, long nights, to allow that fog to develop. And particularly if we see the negative numbers (temperature in degrees Celsius), it can quite stubborn to clear the next day.”

Motorists have been urged to take extra care in the low-lying cloud after a crash involving more than 30 vehicles during foggy conditions saw a motorway closed for nearly 12 hours.

The M20 in Kent was shut both ways between junction 8 and 9 near Maidstone after the pile-up on Saturday evening, which seriously injured two people.

AA president Edmund King previously said: “Fog can transform a familiar road in a matter of minutes, so drivers need to be prepared to adapt their speed and leave more room between themselves and the vehicle ahead.

“One of the biggest mistakes is simply following the rear lights of the car in front. It can give you a false sense of security and means you may be travelling too close to react safely if that vehicle suddenly stops.

“Ultimately, there’s no prize for arriving a few minutes early. Give yourself extra time, slow down and drive to what you can actually see ahead.”