Sub-zero temperatures are reported in many parts of Britain. Freezing conditions are expected on Monday night.
Roads and schools are affected and some flights were hit at Birmingham and Luton airports.
The BBC reports temperatures in some areas were as low as -8 degrees Celsius and were expected to hit -10C overnight.
Parts of northern Scotland experienced the lowest temperatures on Sunday night at -8C; parts of Oxfordshire recorded -7C and Wales and southeast England recorded -5C.
Conditions were due to a strong wind originating from Russia and Scandinavia.
Pensioners have been warned to take extra precautions to stay warm.
However, the cold weather is expected to ease later in the week.
