Air travellers have faced disruption due to foggy conditions causing flights to be cancelled from Heathrow and London City.
The two airports were disrupted throughout Sunday and passengers have been warned that further cancelled flights and severe disruption will impact travel on Monday.
More than 100 flights were cancelled on Sunday as a result of heavy fog in the south east and east of England.
The Met Office had issued a severe weather warning in regions of heavy fog that were likely to become worse on Sunday night and could last until the following morning.
A Met Office spokesman said on Sunday night: "We have seen quite dense fog in the south east and east of England today, and overnight we expect that to become more widespread, with visibility reduced to 50 metres.
"Tomorrow fog will take a while to shift in London, the south east and the east of England up to York, and will only become less widespread in the late morning."
This highlights the need for an appropriate level of travel insurance, including cover for any delays.
Heathrow said that 63 inbound and 78 outbound flights had been cancelled on Sunday due to foggy conditions.
A spokeswoman for the airport said: "Passengers are being re-booked or put up in accommodation by airlines, while some domestic passengers are being taken in coaches to their destination."
© Press Association 2011