Up to 30cm (12in) of snow was expected to fall across much of Britain by the end of today, prompting the Met Office to warn of a "severe weather event".
The south-east of England, including parts of London, Kent, Sussex and East Anglia, and the Pennines were likely to be the areas worst affected by an easterly wind bringing weather from the Siberian steppe.
Temperatures were due to plunge as low as minus 4C, with 30mph (50 km/h) to 40mph winds making that feel more like minus 10C.
There were warnings of "severe disruption" to roads during the Monday afternoon rush-hour in particular, with airports also likely to be affected and the possibility of school closures.
Network Rail said it was not expecting any major problems although trains fitted with snow ploughs were on standby. The snowfalls could be the heaviest since January 2003, when motorists were trapped on the M11, or possibly February 1991, when 2ft fell. This winter is also expected to be the coldest since 1995, when a record-equalling temperature of minus 27.2C was recorded in the Scottish village of Altnaharra.
This week's temperatures are unlikely to get near that mark, but the Met Office said there was a "high risk of a severe weather event" today caused by heavy snowfalls across much of the country.
It said 5-10cm was forecast for many areas of the UK with 20-30cm (six to nine inches) possible, particularly on higher ground. Byron Chalcraft, a forecaster at the Met Office, said: "Monday is likely to be the coldest day of the week. It will probably get to about minus 3C or minus 4C in inland areas of central England.
"It's looking like this winter as a whole will be as cold as 1995, when we had a cold easterly with similar snow-shower events," he said.Reuse content