Heavy snow falling over much of England and Wales is disrupting travel - as forecasters warn of the heaviest and most widespread snow for six years.

Eastern England, the South East, the Midlands and eastern Wales are experiencing heavy snowfall.

Kent, London, Surrey and Hampshire may see up to 6in (15cm) of snow overnight, as temperatures plummet.

Road travel has been severely hit, with one driver on the M25 reporting he saw several jack-knifed lorries.

A BAA spokesman said the runway at Gatwick was closed for two hours between 2000 and 2200 GMT, with 23 flights cancelled and 18 diverted to other airports, but the snowfall had not disrupted services at Heathrow or Stansted airports.

A BBC reporter at Gatwick said many people were stranded at the airport with trains not running and taxis out of service due to gridlock on the M25, and that long queues had built up for hotels.

Runways would be de-iced overnight, but passengers due to fly out on Monday are being urged to double-check their flights are not affected before they begin their journeys.

London City Airport was also forced to temporarily close its runway to de-ice, with flights diverted to Heathrow and Luton.

Transport for London said all London buses had been withdrawn from service due "to adverse weather and dangerous driving conditions", however Scotland Yard said there were no major problems reported.

The Met Office is warning of severe weather for much of the country over the coming days, in what is expected to become the heaviest snowfall since January 2003.

Gritters and snow-ploughs are on standby as the "significant and disruptive" snow moves in.

The London-bound M20 in Kent was closed between junction nine at the Ashford turn-off and junction eight at the Leeds Castle turn-off because of treacherous conditions caused by snowfall.

Mark Underhill, a manager at Trafficlink's south east headquarters, said traffic was moving very slowly between the Leatherhead and Dartford exits of the M25, and advised against travelling on the M25.

He also said the A406 eastbound between Edmonton and Chingford, and the A12 Londonbound from Chelmsford, were also experiencing heavy traffic jams due to snow.

He said minor roads in Kent, Essex and Surrey were likely to be even affected even more.

The Highways Agency said there have been many minor accidents but no major road closures and several collisions have been reported by police, though no-one has been injured.

The agency recommended people should not take any non-essential journeys.

Police in Lincolnshire have reported several vehicles stuck because of snowfall near Grantham.

At junction 13 of the M1, near Bedford, visibility was reported by one driver as "very bad" with traffic doing around 30mph (48kmph) in both directions.

Another motorist, driving in the Midlands, told the BBC conditions were much clearer there, but that highway officers have told him they had responded to 1,735 incidents in the last 24 hours in the East Midlands alone.

BBC Weather Centre forecaster Peter Gibbs said: "We are expecting as much as 15cm of snow across the South East - it's been a few years since we had that amount in that area. It is likely to be very disruptive to travel."

Tom Defty, head of forecasting operations at MetService, said some areas of high ground could see as many as 8in (20cm) of snow.

Icy winds heading for the UK will also make temperatures feel "sub zero" as the coldest winter in 13 years continues. Much of the UK is predicted to see snow, though the Pennines and South East England are expected to bear the brunt.

Night-time temperatures are set to drop to -2C (28F) as a blast of cold air sweeps in from the North Sea.

Mark Munnoch from the Highways Agency said the organisation was well prepared to deal with snowfall over roads after criticism over its reaction to severe weather in 2003.

"The good thing about this weather front that's coming in is we have had advanced notice of it so we are well prepared for this.

"We've increased the number of traffic officer patrols, we've brought in extra staff to our control rooms across the country and our gritter staff are out and about in readiness for this."

On Saturday, winds began gusting at up to 70mph (112km/h) over the hills of northern Britain.

The AA have warned motorists to ensure they keep warm clothes in their vehicles if they were planning to go out.

The organisation's Andy Taylor said: "People often treat their car as an overcoat.

"But when you break down you are suddenly vulnerable to the weather.

"If you break down on a motorway, the safety advice is to get out of the car and wait behind the barrier. Unless you have extra clothes you really are flirting with hypothermia."

Slightly milder air will move in during Tuesday, with snow mainly confined to hills and in other areas precipitation is expected to turn to rain.

[link to news.bbc.co.uk]