Heavy snow sees travel disruption across much of Britain

Snowy scenes as freezing conditions come to the UK

Heavy snow has brought travel disruption to many parts of Britain, with the threat of more delays later.

London Heathrow has cancelled up to a third of its flights for the day, while other airports in England had runway closures and cancellations on Saturday.

Problems were reported on a number of roads overnight, including the M40, where up to 100 vehicles were stranded.

Up to 15cm (6in) of snow has fallen in some parts over the past few hours, although the snow will ease by dawn.

Snow fell over parts of Scotland, Wales, northern England and the Midlands on Saturday before sweeping down to London and East Anglia.

Church Fenton, in North Yorkshire, reported 16cm (6in) of snow.

Met Office severe weather warnings remain in place with amber "be prepared" warnings for snow and ice across most of Britain, and yellow "be aware" alerts for the Highlands and Northern Ireland.

Heathrow operator BAA said it was cancelling one-third of Sunday's approximate 1,200 flights.

There were some delays on Saturday night due to visibility problems, with a number of other airports reporting delays, diversions and cancellations because of the weather.

On the roads, police said as many as 100 vehicles were stationary on the M40 between Junction 4 High Wycombe and Junction 9 Bicester for several hours and snow ploughs were brought in to help clear the roads.

One motorist told BBC News he had spent more than seven hours stuck in traffic in his car on the M25 in Hertfordshire.

Transport for London said several Tube lines were hit by suspensions or delays because of the weather late on Saturday.

This included the Central Line, where passengers became stuck on a train that broke down between Snaresbrook and South Woodford and say they were asked to walk 15 minutes down the tracks to the next station.

Air passengers at London's Heathrow, Gatwick and Stansted airports have been advised to contact their airline for more information about flights on Sunday.

British Airways said it would allow passengers scheduled to fly on Sunday to re-book for journeys between Monday and Thursday.

Snow fell across London through much of Saturday evening

Richard Scott, from BAA, said because Heathrow operated at capacity, there was no slack in the system to deal with the reduced number of flights that could take off and land in bad weather.

He added: "If you can imagine you're driving, you have to drive slower, leave more space for the car in front in fog, strong winds, snow. It's the same with aircraft.

"If we don't proactively cancel flights, the delays build and build and build and it's much worse for passengers."

Flights were diverted from Luton airport as it closed its runway on Saturday night, which also caused three departing flights to be cancelled.

Stansted airport in Essex closed on Saturday night for a period to clear snow from its runway, while Birmingham Airport said it had been clearing snow from the airfield and runway.

Leeds Bradford Airport has warned of delays or cancellations.

'Dangerous cocktail'

The RAC's Kevin Andrews said heavy snow and sub-zero temperatures would create "a dangerous cocktail of driving conditions" and urged drivers to stay at home where possible.

Treacherous driving conditions are expected on Sunday morning

Forecasters said a band of wet weather had turned to snow as it moved south and east across mainland Britain during Saturday.

BBC Weather forecaster Alex Deakin said there was still some snow falling across East Anglia and the South East, but it would stop falling quickly after dawn.

He added the main concern for Sunday was icy roads.

February has seen daytime temperatures plunge four or five degrees lower than average over the past few days.

A temperature of -12.4C (9.7F) was recorded in South Newington, Oxfordshire, on Friday night - the lowest this season, the Met Office said.

The cold conditions are likely to continue into the early part of next week.

The Local Government Association said motorists were being advised to check the latest weather and gritting updates on council websites and "gritter Twitter" feeds.