Dense fog is set to force air travel delays and cancellations at London area airports for the third day in succession.

British Airways warned that thick fog across parts of southern England will affect some flights today (Wednesday).

The carrier is “slightly reducing” its Heathrow flight schedule, while other flights may face delays.

“We are also expecting further fog at Gatwick and London City airports to affect some flights,” BA said.

“We are sorry for the difficulties caused by the poor weather and will do all we can to minimise the effect it has on our operations.”

At least 100 flights at Heathrow were cancelled on both Monday and Tuesday with freezing fog affecting operations at other southern airports including Southampton.

Heathrow said: “Foggy weather across London and the south-east is expected to continue until Wednesday and some passengers may experience disruption to their journey as a result.

“Heathrow advises passengers to check their flight status with their airline. Heathrow’s top priority is the safety of passengers and we apologise to those whose travel has been affected.”