Snow is expected across the country, with yellow weather warnings in place across all four nations.
Image source, PA MediaTemperatures are set to fall as low as -10C with snow forecast for parts of the UK including London, the South East and Scotland, the Met Office warns.
Over much of Kent and Sussex a yellow alert is in place for Monday morning.
Yellow warnings for ice have also been issued for parts of Northern Ireland, Wales and northern England.
The cold snap comes after widespread flooding left parts of the UK submerged over the weekend – with more than 140 alerts still active.
Temperatures are expected to drop overnight to -2C in London, -1C in Cardiff, and -3C in both Edinburgh and Belfast, while parts of the Scottish Highlands could drop as low as -10C.
According to the Met Office snow and ice will cover northern Scotland through to Wednesday morning.
Snow is forecast to fall across parts of south-east England overnight from Sunday night into Monday.
Across north and parts of mid-Wales the Met Office has issued a yellow warning for ice.
Met Office meteorologist Craig Snell said those driving to work on Monday should leave plenty of time for their journeys.
“This could be a problem during rush hour, it could cause a few problems on the roads,” he said.
“The risk of flooding is still there.”
Image source, PA Media
The spell of cold weather follows a weekend of flooding.
The Environment Agency has 86 flood warnings in place, meaning flooding is expected.
Also, 141 flood alerts remain in place largely in parts of west and south-west England – meaning flooding is possible.