The Met Office has issued a yellow warning for fog, affecting London and the south east.
Flights in and out of Heathrow may be affected, with the airport confirming via Twitter that some planes have been delayed due to weather conditions.
Hi Jeff, yes we are experiencing some delays due to the fog. Thank you
— Heathrow Airport (@HeathrowAirport) November 2, 2017
Flights in and out of London Gatwick may also be affected by the fog.
"Fog patches have developed overnight and have become more widespread towards dawn," the Met Office said.
"Fog may be slow to clear through Thursday morning. Longer journey times and hazardous driving conditions are possible. This is an update to pull the area further east given prevalence of fog patches this morning."