Heavy snowfall overnight has caused major travel disruption, leading to road closures as well as flights and trains being cancelled.
Amber and yellow snow and ice warnings are in place across the North East, the Midlands, the East of England and the South East, the Met Office said, with delays, closures and stranded vehicles expected.
Rural communities could be cut off completely, with power cuts and disruption to mobile phone signals possible throughout Tuesday, it added.
Here are the latest reported issues.
Slow-moving traffic is causing delays on the M2 Kent westbound, between junctions seven and five, Highways England said.
HGVs struggling in the snow have caused delays on the M20 in both directions between junctions eight and nine, adding up to two hours to journey times, it added.
The A249 in Kent remains closed following a crash between two lorries.
Snow continues to fall across much of Kent with significant accumulations, as shown on these @HighwaysEngland webcams of the M20. Snow amounts do vary between junctions though so take care and remain #weatheraware pic.twitter.com/UgIblCw5hS— Met Office (@metoffice) February 27, 2018
Meanwhile, dozens of stranded motorists had to be pulled from snow drifts on Tuesday morning, the AA added.
Vince Crane of the AA said: “With the sub-zero temperatures this week, drivers should allow extra time to properly de-ice the car and check their route before setting off – try to favour gritted roads if possible.
“Accidents happen when people rush so when on the road, leave plenty of space behind the car in front and drive to the conditions.”
Several train companies have been hit by cancellations and disruptions on Tuesday, and services are expected to be extremely busy.
National Rail Enquiries said severe weather was affecting services on C2C, Greater Anglia, London Overground, South Western Railway, Southeastern, Stansted Express, and TfL Rail.
Disruption may continue through Tuesday, Wednesday and Thursday, Network Rail said.
It urged customers to check services before travelling.
London Overground is running a stripped-back service, with between two and four trains per hour on many routes, and no services on other lines, such as between Romford and Upminster.
â ï¸ IMPORTANT: c2c will be running a limited service only today (Tuesday) and advises passengers not to travel where possible . Check for more details - https://t.co/jExzuIoHtc— c2c Rail (@c2c_Rail) February 27, 2018
C2C is operating a limited timetable on Tuesday and advises its customers not to travel where possible.
Greater Anglia is also running a limited service, with less frequent and slower services between Norwich and Ipswich and cities like London and Cambridge.
#uksnow Cold-weather vehicles are in position at depots across Britain, including 10 Snow & Ice Treatment Trains > https://t.co/FqxpwWa3sU— Network Rail (@networkrail) February 26, 2018
In event of snow, teams will clear key junctions and if required use ploughs to clear lines. Check @nationalrailenq for latest travel info. pic.twitter.com/KPu9N5DrMO
Trains between Norwich and Lowestoft, Felixstowe and Great Yarmouth are cancelled, among others.
Southeastern said it expects to run a normal timetable on Tuesday, but if conditions worsen an emergency timetable may be introduced.
British Airways cancelled dozens of flights from Heathrow Airport on Tuesday, while easyJet said it is expecting some disruption.
British Airways said in a statement it was preparing for adverse weather from Monday February 26 to March 2, saying it was “likely to affect some of our short-haul and domestic flights”.
It added: “It is likely at times we will have to proactively cancel some services and re-book customers on to alternative flights.
“Customers on cancelled services can also claim a full refund if they no longer wish to travel.
“We are sorry for the potential disruption to your travel plans and are doing all we can to minimise the effect the poor weather may have on our flights.”
North-east England and Scotland are expected to see the heaviest snow from Wednesday morning, with 15-25cm likely across Scotland, the Met Office said.