Forecasters have warned of icy conditions as many Britons head back to work after a weekend of snow.
The Met Office has issued nine severe weather alerts, warning ice could be a hazard on roads and pavements across much of England and south-east Wales.
A 25-mile long section of the A1 northbound in North Yorkshire was shut this morning following a series of accidents in what police described as "treacherous" conditions.
No-one is thought to have been hurt in the collisions on a long stretch of the road between Allerton Park, near York, and the Catterick area.
A spokesman said: "Traffic conditions on the A1 northbound from Dishforth and all the way to Leeming and beyond are treacherous.
"There have been a serious of accidents which have resulted in the A1 northbound being shut while emergency services clear the scene."
The spokesman said the incidents involved jack-knifed lorries and other vehicles which had taken evasive action.
Copyright Press Association 2012