After a cold night, Britain woke up to a blanket of snow on Sunday.

Icy conditions, with heavy snowfall of up to 16 cm, has brought road and rail traffic to a standstill in many parts of Britain. Several flight services have also been cancelled.

Extreme road conditions forced several motorists to spend their nights in their cars.

The worst of the snow will move eastwards, but the Met Office, the UK's official weather agency, has issued a level three alert, which means severe cold weather and icy conditions, for all the nine regions of England between Sunday and Thursday. Outbreaks of light rain spreading southeastwards later today and overnight, with some snow across some east/southeastern parts. This leading to a continuation of the icy conditions for many parts into Monday. A return to more settled but again colder conditions from Tuesday as easterly winds become established, the Met Office said on Sunday.

On Saturday, snow fell over parts of Scotland, Wales, northern England and the Midlands, the BBC reported.

A third of Sunday's flights have been axed at London's Heathrow Airport amid adverse weather conditions and the possibility of freezing fog, Associated Press reported. A Heathrow spokesman said: We have about 850 of our usual 1,231 flights scheduled for today. That's been agreed with the airlines, but we are asking people to check with their airlines before travelling to the airport.

UK snowfall
People walk their dogs in the snow at Lyme Park near Manchester, northern England December 16, 2011. Reuters
UK snowfall
Jim Ferrie casts a line on the opening day of the salmon fishing season on the river Tay, in Dunkeld, Scotland January 16, 2012. Reuters
UK snowfall
Members of the public skate on the frozen fens in Welney, south east England February 4, 2012. Heavy snow is forecast for many parts of Britain later on Saturday and Sunday, and the Met Office has issued severe weather warnings for numerous areas of England, Scotland, Wales and Northern Ireland, local media reported. Reuters
UK snowfall
Seagulls stand on ice covering a pond in Hyde Park in London February 4, 2012. Heavy snow is forecast for many parts of Britain later on Saturday and Sunday, and the Met Office has issued severe weather warnings for numerous areas of England, Scotland, Wales and Northern Ireland, local media reported. Reuters
UK snowfall
A groundsman (2nd L) clears snow from the lines during the English Premier League soccer match between Manchester City and Fulham at the Etihad stadium in Manchester, northern England February 4, 2012. Reuters
UK snowfall
Snow gathers on a London underground Tube sign in Bethnal Green, east London, February 4, 2012. Reuters
UK snowfall
A snow-covered bicycle is tied to a railing in Bethnal Green, east London, February 4, 2012. Reuters
United kingdom Winter