As the icy weather set to continue, the UK could be heading for its coldest December since 1890, forecasters said.
Temperatures were expected to remain below freezing on Boxing Day with spells of rain, sleet and snow in northern Ireland, Scotland and parts of west Wales and far west England, spreading eastwards overnight.
But they added that temperatures could rise as high as 10C (50F) by the middle of next week as a new weather system moves in from the Atlantic.
Those braving the bleak mid-winter to get away for Christmas yesterday faced reduced rail services, icy roads and continuing cancellations and delays to flights.
A number of train companies ran amended timetables, with some services axed on the main London to Scotland routes up the east and west coast.
The RMT transport union said it was "scandalous" that train companies could bring in "special" timetables and avoid financial penalties.
British Airways operated all its long-haul flights at Heathrow airport as well as the vast majority of short-haul services.
Where possible, BA flew larger long-haul aircraft to European cities on Christmas Eve to increase its seat capacity. The airline was also hiring extra aircraft to help fly as many passengers as possible.
Away from Heathrow, other UK airports had to cancel some short-haul flights due to the continuing bad weather in Europe.
The AA said call-outs on Christmas Eve were still 40% above normal due to last-minute Christmas shopping and getaway traffic.
It added it expected to cover around 13,000 breakdowns by the end of December 24 compared with just over 9,000 on a normal Friday.
The Highways Agency advised motorists to take extra care and be mindful of difficult driving conditions, with low temperatures forecast over the weekend.
Police and coastguards were yesterday called to help a number of drivers stuck in cars after a snap blizzard hit the Whitby area of North Yorkshire.