Motorists in some areas have been told to keep out of their cars because of Easter snow in Scotland and England.
Snow has hit the Scottish highlands, north-east England, the Midlands and the south-east, with north-east England the worst affected area.
There have been icy roads and up to 10cm (3.9in) of snow. Motorists have been warned not to travel unless absolutely necessary.
The snow spread into England after falling in Scotland overnight.
The BBC Weather Centre said that during the morning there were "very treacherous" conditions on the roads.
Humberside Police, as well as police in Lincolnshire, Staffordshire and Derbyshire, warned motorists either not to go out unless their journeys were essential, or to drive with caution.
Three men had to be rescued from Scafell Pike, England's highest mountain.
The mountaineers, who are safe and well, were rescued by 12 members of the Wasdale Mountain Rescue team.
In Cumbria, the A66 was closed to all vehicles and the police were urging motorists to take extra care on minor roads.
A number of lorries became stuck and the snow gates were closed on both the Cumbria and Durham sides of the A66. The Highways Agency was using snow ploughs to clear the route.
The North West Ambulance Service appealed to members of the public to call 999 only as a last resort.
At one point, a vehicle from Sedbergh became trapped in heavy snow and needed the help of a mountain rescue team to get free.
Safari park closed
A North Yorkshire Police spokesman had described the roads as "horrendous" earlier in the morning, but that virtually all roads were clear by lunchtime.
Heavy snow also fell overnight and into the morning in East Anglia.
A Norfolk Constabulary spokesman said: "We're currently getting a run of minor accidents where people are slipping off the road.
"There is snow on the ground in the west of the county but it's not causing too many problems."
In Bedfordshire, the weather forced the closure of Woburn Safari Park.
Spokeswoman Cheryl Williams told Three Counties Radio they were concerned for the safety of people in vehicles.
She said they were also worried that if cars skidded off the roads, they might hit some of the animals.
The west of England will largely escape the snow, but will experience wintry showers of rain with sunny spells. Temperatures in these areas will hover around 6C or 7C.
In Wales snow is only likely on the hills, with damp weather in lower-lying areas such as Cardiff and Swansea.
No snow is expected in Northern Ireland, which has had a bright start and where more bright sunshine is predicted for the afternoon. But it will remain cold with temperatures not much higher than 8C.
Snow will continue to fall in the highlands of Scotland throughout the morning and afternoon, but the showers will be interspersed with sunny spells. The temperature there will remain at about 6C.