The Met Office has issued yellow warning for fog for Thursday evening and Friday morning.
More than 40 flights were cancelled across the UK this morning as thick fog covered England and parts of Scotland.
Thick fog across England and parts of Scotland is causing travel disruptions as the Met office extended the yellow warning for fog until 11 am.
Flights have been cancelled or delayed at a number of airports.
Daybreak weather presenter Laura Tobin has said the dense fog will clear away before lunchtime:
Flights across the UK were cancelled due to low visibility as the Met office issued yellow warning for fog.
Following airports are affected:
The Met office said the fog will be slow to clear, with visibility below 100 meters in many places across England and south west Scotland.
The skies should be clearer by midday.
There is disruption to flights to/from Land's End Airport due to fog. Passengers are advised to contact Skybus for the latest information. Flights may be delayed or cancelled
A number of domestic flights from London have been cancelled because of early-morning fog.
Arrivals and departures were cancelled at London City Airport where forecasters said visibility was down to below 100 metres.
"The fog is quite extensive across much of England and Wales this morning, and quite a few places will be waking up to quite foggy conditions," said Chris Burton, from forecasters MeteoGroup.
Several flights at London City Airport were cancelled this morning due to thick fog and low visibility across England and south west Scotland.
The Met office issued yellow warning for fog in England and parts of Scotland. Travel disruptions are expected elsewhere.
Train travel difficulties are continuing this morning.
Overhead wire problems between Northampton and Rugby meant buses replaced trains between Northampton and Coventry, while an hourly train shuttle was running between Coventry and Birmingham New Street, with journey times in the area extended by up to an hour.
There were also overhead wire problems affecting services in and out of London's King's Cross station.
The bad weather disrupted services at Christ's Hospital in Sussex, with trains between Barnham and Horsham delayed.
A broken-down train at Melton Mowbray in Leicestershire led to delays of up to 45 minutes between Leicester and Peterborough.