Snow flurries and plunging temperatures are set to threaten Thursday's commute with large parts of the country covered by warnings of ice.
A wet Wednesday gave way to clearing skies overnight, bringing freezing conditions ideal for a hard frost and icy patches, with motorists and commuters urged to take care when they get on the move.
The Met Office has issued two yellow warnings of ice and a yellow warning of snow that cover most of mainland Britain and Northern Ireland and are due to stay in place until 10am on Thursday.
Rail operators warned of potential disruption to services and icy platforms, while forecaster Jenna MacGregor said road users should be on the lookout for "slippery surfaces".
She said: "We have a yellow warning for snow covering East Anglia and western parts of Lincolnshire and two ice warnings running on a diagonal from the South West up to Yorkshire in an area encompassing Wales and the Midlands.
"We have another ice warning covering West Scotland and Northern Ireland and they are all out until 10 o'clock.
"There is a band of rain that is moving eastwards that could bring some flurries of snow and sleet, but because that has been moving through overnight there could be some frost and icy patches on untreated roads when skies clear."
Temperatures in the warning zones are expected to drop to around freezing, dipping below to minus -1C (30.2F) in some places.
South West Trains advised customers to watch out for icy platforms and warned there could be disruption to services should ice build up on electric rails, although special deicer trains were working through the night to clear routes, a spokesman said.