While Scotland and the north of England were blessed with mild weather, the icy snap dominated the South. The big freeze also made driving tricky in southern parts and hit rail services.
The conditions sparked travel warnings after reports of multiple crashes during the morning rush hour with commuters warned of icy roads and low visibility from fog.
While temperatures reached 50F (10.1C) in Kinlochewe in the Scottish Highlands, the mercury plunged to -9.5C in Santon Downham, Suffolk.
Heathrow recorded its coldest night since December 2010 – and its chilliest January night since 1987 – as temperatures dropped to a teeth-chattering -8.4C.
The icy conditions at Britain’s busiest airport led to the cancellation of more than 80 British Airways flights affecting some 12,000 passengers expecting to fly to destinations such as Amsterdam, Edinburgh, Milan, Paris and Stockholm.
It followed around 70 cancellations at the airport on Sunday due to freezing fog.
Airlines were warned at the weekend they would have to reduce flights at Heathrow by about 15 per cent due to the weather and air traffic control restrictions.
And temperatures at the airport yesterday morning were still as low as -6C, with visibility also poor.
Online departure boards at Heathrow showed widespread cancellations to destinations also including Berlin and Miami. British Airways said it had “apologised to customers whose flights have been affected” and it was “doing everything we can to get them on their way as quickly as possible”.
It advised customers to check its website before travelling to the airport. But passengers took to social media to voice their frustrations over the disruption.
One tweeted: “I was supposed to fly yesterday, got cancelled and rebooked to today. Cancelled again, rebooked to tomorrow. What’s happening?”
Another passenger wrote: “My flight to Milan cancelled! No seats available on alternative flights, now had to cancel a week’s worth of business in Italy! #Heathrow.”
The spokesman for Heathrow stressed that poor visibility was still affecting the airport, with similar conditions across the
Freezing fog is defined as when the visibility…