Bitterly cold weather has spread across the UK, cancelling trains and sparking fears of flooding.
Many areas woke to snow, ice and frost, and there were early morning rail delays from as far north as Glasgow and south towards Chichester.
Snow and cold weather warnings are in place for large chunks of the country and there is not expected to be a significant break in temperatures for days.
A major incident was declared on Wednesday for parts of Somerset where flooding is expected, the Environment Agency said.
Tuesday was the coldest day of winter this year, with a low of minus 9.8°C in Topcliffe in North Yorkshire.
The first two weeks of December were the coldest start to meteorological winter since 2010, and on December 13 there was a minus 17.3°C recorded in Braemar, Scotland.
The Somerset alert comes after dozens of people were injured in a crash involving a double-decker bus in “treacherous” freezing conditions in Somerset.
“There will be a fair amount of ice around so there are a lot of warnings in place,” said Met Office meteorologist Tom Morgan.
“Certainly if you're planning to make a journey [on Wednesday] it's worth leaving extra time for your journey, both to defrost your car and because the roads will be more slippery. There will be travel disruption, especially where there is snow.”
Mr Morgan said most warnings will expire around the middle part of Wednesday but further warnings expected to come into force.
The weather service generally avoids issuing warnings long in advance so as not to confuse people.
“This is a cold spell lasting around five to seven days so I think by the weekend if you're living in Scotland or Northern Ireland, you will feel it getting a bit milder — but it will remain cold in England and Wales.”
An amber warning for snow in northern Scotland has been issued by the Met Office for between 3pm and 11.59pm on Tuesday.
The Met Office said 32cm of snow fell at Loch Glascarnoch in the Scottish Highlands on Tuesday morning.
Nearby Altnaharra saw 11cm, Wick Airport on Scotland's far north coast had 8cm and Lerwick in the Shetland Islands had 7cm of snow.
Ballypatrick Forest in County Antrim and Shap in Cumbria each saw 3cm of snowfall.
Yellow warnings for snow and ice are in place for most of Northern Ireland and parts of the North West, Midlands and Wales from noon on Tuesday until noon on Wednesday, and in the south-west from 6pm on Tuesday until noon on Wednesday.