The airport's largest carrier, British Airways, has cancelled around 80 of its own flights this morning the largest carrier at the UK's busiest airport, has axed around 80 flights and 'apologised to customers whose flights have been affected" and said it was "doing everything we can to get them on their way as quickly as possible".
The Meteorological office has indicated that the warning for fog will last until 11:00 at the earliest and could continue to affect operations later in the day.
A spokesperson for the airport said "While there may be minor changes to schedules as a result of the weather, we want to reassure passengers that our colleagues are working in close collaboration with our airline and air traffic control partners to get them safely away on their journeys as quickly as possible,"
A number of flights that were due to arrive at Heathrow over the course of last night and this morning have also been delayed because of the conditions at the airport, some as much as 12 hours.
London Gatwick has not experienced the same level is weather related disruption with most flights arriving or departing on time.
London Gatwick has not experienced the same level is weather related disruption with most flights arriving or departing on time.