Thousands of households have been left without power as heavy snow swept the UK and brought parts of the country slipping and sliding to a halt.

Hundreds of flights were cancelled at Britain's busiest airport while train companies axed rail services and roads were closed.

Motorists were urged to avoid all but essential journeys amid strong winds, plunging temperatures and blizzards which sent several cars spinning into ditches.

The arctic blasts forced nearly 2,000 schools to shut their doors, meaning some sixth-form and college students had their A-level exams postponed.

But the weather heaped misery on more than 10,000 households in South Wales, where residents found themselves with no power. Western Power said it was working to resolve the problem and later restored electricity in half of the homes affected.

It came after the Met Office issued a "red" severe weather warning for heavy snow in Wales, which experienced the worst of the snow, with some 25cm falling at Sennybridge, in Powys. Scenes of panic-buying were reported in stores across the West Country, Home Counties and south Wales as stores ran low on stock.

Meanwhile several airports were forced to ground flights or close following thick snow flurries and near galeforce winds of 30mph.

A spokesman for Heathrow - which shut both runways for periods during the day to clear snow - said 369 flights were cancelled. Bristol and Birmingham airports closed for a time while Southampton stayed shut for most of the day.

Rail travellers also experienced upheaval as operators scrapped services. Poor conditions - which saw between 5cm and 10cm of snow settle across much of the country - also caused severe hold-ups and several prangs on the roads.

The Met Office - which issued Amber alerts for the Midlands, London and the South, the east of England, the South West, the North West and Northern Ireland - warned snow and ice could continue to wreak havoc.