Many people woke to a cold and icy start on Tuesday as overnight temperatures plummeted to as low as minus 10C (14F) in some parts of the country.
Scotland saw the chilliest temperatures, with the mercury dipping to minus 10.5C (13.1F) at Tulloch Bridge and Braemar in Aberdeenshire not far behind with minus 10.1C (13.8F).
John Lee, forecaster at MeteoGroup, the weather division of the Press Association, said parts of northern England also shivered overnight in some of the coldest weather.
Parts of Cumbria dropped to as low as minus 6C (21.2F), while many others parts of the country hovered around minus 1C (30.2F) and minus 2C (28.4F).
Mr Lee said: "Across the board there was a very widespread frost - only a few coastal areas escaped the worst of it."
The cold snap looks set to continue for the rest of the week and Tuesday night could be just as chilly.
Mr Lee said on Tuesday: "It is turning unsettled from Thursday night onwards but for the next couple of days at least it's going to stay very cold.
"Tonight, temperatures look like they could get similarly low to last night; minus 8C (17.6F) is possible in parts of Scotland but I wouldn't rule it out for parts of England as well.
"Tomorrow night as well there's a fairly sharp frost. At the moment it looks like minus 4C (24.8F) and minus 5C (23F) is possible for some parts."
The weather for the rest of Tuesday is forecast to include bright spells with the chance of some wintry showers in northern Scotland, and local wintry showers on North Sea coasts in England.