Early morning flights between Scotland and London have been cancelled as ice and thick fog descended on the UK overnight.
Temperatures fell to a low of -10C and there was a widespread heavy frost across the country.
The coldest spot in the UK last night was Tulloch Bridge in the Highlands, where the thermometer could only creep up to minus 10.2C (13F) .
Aberdeen flights were a victim among Heathrow Airport's 60 cancellations and many more delays, according to its website. The airport began reporting flight cancellations last night and have cancelled more this morning.
Other flights hit were scheduled trips to Warsaw, Nice, Stockholm, and several German cities.
London City Airport also cancelled six early morning flights to Edinburgh and European cities, and reported a number of delays on its arrivals board.
In Scotland, a broken-down train at Bathgate also led to delays between Edinburgh and Airdrie.
A message on the airport's Twitter page said: "Visibility has not improved, flight disruptions are present & expected to continue until further notice. Please call your airline for info."
Large swathes of the UK will be affected by freezing temperatures. Nick Prebble, a forecaster for MeteoGroup, said: "It will be a bitterly cold day wherever you are in the UK, and very grey where the fog lingers."
However, the cold weather is set to improve on Thursday.
Matt Dobson, a senior forecaster with the Press Association's weather division, MeteoGroup, said: "This cold spell won't last. The fog will lift. But although the big change on Thursday night, with an Atlantic front moving in, will mean higher temperatures, there is likely to be a lot of wet weather.
"The south of England could be very wet on Friday and we are likely to see wet conditions all the way up to Christmas.
"The exception could be a short, cold snap in the weekend before Christmas."