Travellers have battled ice, snow and bitterly cold winds as winter returned.
Jersey Airport was shut due to snow, and on the roads there were hazardous conditions on many major routes.
Blizzard conditions were reported on the M40 in Warwickshire and there were numerous rush-hour accidents. Strong winds added to drivers' problems, with falling trees blocking some roads. On the trains, poor rail conditions led to delays in Sussex and Hampshire, while there was also a number of signalling problems.
Forecasters warned of snow spreading to nearly every area of Britain, with almost 4in (10cm) expected in the worst-hit areas. With more snow showers expected throughout the week, bookmakers slashed the odds for a white Easter.
On the roads, there were hazardous driving conditions on the A69 and A6 in Cumbria and on the A54 in Cheshire. In Sussex, police said there had been "a number" of crashes caused by the snowy conditions as they warned motorists to take extra care on the roads. A Sussex Police spokesman said: "There's not a great deal of snow falling at the moment, but the temperature is hovering at or just below freezing and the roads are slippery in places. Some drivers are just not making allowances for the conditions."
While drivers contended with heavy snow on the M40 in Warwickshire, motorists in Wales had to put up with strong winds. One lane of the M48 Severn Bridge was closed and falling trees blocked some Welsh roads. Some of the roads where driving conditions were at their worst included the A46 in Nottinghamshire, the A14 in Suffolk and the A353 in Dorset. Fallen trees blocked roads in Newquay in Cornwall and in Lynton in Devon.
On the railways, a signalling problem caused delays between Moorgate and Finsbury Park in north London, while another signalling problem led to hold-ups in the Carstairs area of Scotland, which affected services run by five companies - CrossCountry, East Coast, First TransPennine Express, ScotRail and Virgin Trains. At Aldermaston in Berkshire, a lineside equipment problem caused delays to train services between Newbury, while a signalling problem meant there were hold-ups for Greater Anglia passengers between Lowestoft and Ipswich.
On the Isle of Wight the bad weather meant no rail services were operating between Shanklin and Ryde Pier Head, with minibuses running instead. On the mainland, signalling problems in the Portsmouth Harbour area and poor rail conditions between Havant in Hampshire and Pulborough in West Sussex meant delays for London-bound commuters.
Condor Ferries services between Jersey and St Malo were affected by the bad weather. There was also a reduced service on TransEuropa Ferries' crossings between Ramsgate and Ostend, while services on Stena Line between Holyhead and Dublin were also reduced. Stena Line also had to cancel its 9am Rosslare to Fishguard service.
Julian Mayes, a forecaster with MeteoGroup, the weather division of the Press Association, said temperatures would struggle to reach 0C (32F) anywhere in Britain. He went on: "The cold weather is set to continue until Thursday but today will be the coldest day. Monday, Tuesday and Wednesday nights are all expected to be very cold and frosty, with overnight temperatures as low as minus 6C (21F) in places. By Friday the wind will have eased off and temperatures could reach 7C (45F). That's still below average for the time of year, but will seem much warmer after this cold snap."