The Met Office has issued yellow weather warnings for snow until midday in parts of northern England, as well as southern and central Scotland.

The most severe snow is expected over higher ground - with up to five to 10cm in some areas.

Scottish areas set to be affected include Clackmannanshire, Falkirk, Perth and Kinross, and Stirling.

Strong winds of up to 35 to 45mph in places will probably lead to difficult travel conditions across higher Pennine and Cumbrian routes, as well as the Southern Uplands.

The A66 has been shut after overnight snowfall between Scotch Corner in north Yorkshire and Brough in Cumbria made the route impassable. The snow is expected to continue falling throughout the morning in some places in the northeast of England.

"Temporary blizzard conditions may be encountered above around 300 or 400 metres elevation," the Met Office said.

"These conditions will probably move into some hillier central parts of Scotland during Sunday morning, while snow turns back to rain further south."

The Met Office said some "short term" loss of power and other services is possible during the period of the warnings.

Meanwhile, a yellow rain warning was issued for County Armagh and County Down in Northern Ireland until 9am on Boxing Day.

Between 25mm and 40mm of rain was forecast, with up to 60mm possible.

After the recent wet weather there, local flooding is a risk.

The Met Office confirmed it had been a white Christmas in parts of the UK, with people waking up to snow in Shetland, Aboyne, Strathallan and parts of the Pennines.