Really??? you're kidding... AAIB:-
At 0720 hrs, the wind was variable in direction at 1 kt, visibility was 3,100 m, the temperature was -5° C, the dew point was -5° C and QNH was 1010 hPa.
At 0738 hrs, the wind was variable in direction at 1 kt, visibility was 1,300 m, the temperature was -6° C, the dew point was -6° C and QNH was 1010 hPa.
At 0804 hrs, the wind was variable in direction at 1 kt, visibility was 5,000 m, the temperature was -5° C, the dew point was -5° C and QNH was 1011 hPa.
Much of the area was prone to widespread low cloud, poor visibility and patches of freezing fog. Cloud bases were in the range of 100 ft to 400 ft agl at 0800 hrs. Visibility was generally below 4,000 m, with several areas of London, including London City Airport, reporting freezing fog with visibility of approximately 700 m.
Visibility at nearby airports (London Heathrow, London City and Royal Air Force Northolt) was generally less than 4,000 m at 0800 hrs, and as low as 700 m at London City Airport. Freezing fog was forecast for Redhill and Elstree Aerodromes, and at London Heliport until 1000 hrs.