The first wave of snow dusted eastern England, with a second heavier band expected to move south and east across the country later.
The Met Office has upgraded its “cold weather action” warning to level three – one underneath a national emergency – for all of England, urging social and healthcare services to target specific actions at high-risk groups.
And there is no sign of the cold weather easing. Temperatures are expected to drop further to around -8C on Wednesday night with the possibility of more light snow flurries.
“The heaviest falls of snow (on Monday) will be across north east England, the east Midlands, East Anglia and Home Counties, where a further two to five cm could fall at lower levels and five to ten cm over the hills and mountains,” said Channel 4 News Weather Presenter Liam Dutton.
“Elsewhere, a wintry mix of rain, sleet and hill snow is likely, with any snow less likely to settle.”
Sleet and snow will ease overnight, but ice will be a concern across all of the UK as temperatures widely fall below 0C, he added, freezing any moisture on the ground.
The west of England and Wales will be warmer, with temperatures rising up to 8C, while in Scotland, snow which fell over the weekend is expected to linger, with the possibility of a light fresh dusting today.
The band of snow is expected to stall overnight, bringing a risk of further falls in Norfolk and Suffolk, but the rest of the country should see a dry Tuesday.
The bad weather hit some rail services, although not all the problems encountered by commuters today were weather-related. Poor conditions led to delays to First Capital Connect services between London and Cambridge.
The AA warned that 75 per cent of drivers are not prepared for conditions on the roads, and urged drivers to carry an essential winter kit and check their cars before getting behind the wheel.