© UnknownPeople walk past near Edinburgh Castle, as heavy snow continues to fall on Scotland.
M8 motorway between Glasgow and Edinburgh blanketed in snow trapping motorists, while major airports are forced to close

Fresh blizzards closed Scottish airports and disrupted rail travel as the army was called in to help ambulance crews reach patients trapped in remote areas.

Hundreds of drivers were stuck on the main route between Glasgow and Edinburgh as the snowy conditions blanketed the central belt of the country. Others opted to bed down in their offices rather than face the long commute home.

Breakdowns and drifting snow blocked major roads. Lothian and Borders police forces said there had been "numerous" problems that brought traffic to a standstill.

"We are trying to remove vehicles from the road and get people that have been stuck," said a police spokesman. "We are looking to put gritters and snowploughs out to clear the carriageway [on the main road between Edinburgh and Glasgow]."

One driver, Mustafa Elshani, said he had been stranded on the M8 for eight hours during a 17-mile journey that normally takes 30 minutes. "I left work early because of the snow chaos," he told Sky News.

"Some families are stuck in their cars, some car batteries are running out. People are totally desperate. There's absolutely no one coming to help. We're just being left here, stranded."

Military 4x4 vehicles were helping medics from the Scottish Ambulance Service reach patients. Pauline Howie, chief executive of the Scottish Ambulance Service, said: "Ambulance crews are battling through horrendous conditions across the central belt, and the additional 4x4 vehicles from the military provides valuable operational assistance to our teams."

The Met Office said that there was between 10cm and 40cm of lying snow in the central lowlands, around 32cm in Edinburgh and 11cm in Glasgow. Both Glasgow and Edinburgh airports were closed for part of the day. Dundee, Inverness, Kirkwall and Campbeltown airports were also closed.

Motorists were advised to drive only if their journey was absolutely necessary, and roads throughout the country were closed. Tayside was the only region with no major routes closed, but drivers were warned to exercise "extreme care" behind the wheel.

In the Highlands a bus with 21 passengers on board slid off the road in the wintry conditions and collided with rocks. No-one was injured and a spare bus was sent so the passengers could complete their journey.

The Forth Road Bridge was closed southbound from around 11am due to a jack-knifed lorry but reopened at 3.30pm. Motorists were warned that a large backlog of traffic had built up and it would be some time before the road cleared.

While 95% of schools in Scotland reopened, many schools sent pupils home early due to the weather. Temperatures are expected to plunge as low as minus 13C in central Scotland and parts of the north.

Severe weather warnings for icy roads were in place throughout the country, with further warnings of snow in Orkney and Shetland and the Highlands & Eilean Siar.

The Scottish government said more than 160 vehicles and almost 400 staff were working "round the clock" to keep the road network moving.

The Scottish transport minister, Stewart Stevenson, said: "Scotland has been in the grip of the worst snow and ice conditions in the early winter since the 1960s. Every effort has been made to keep disruption to a minimum.

"Snow was predicted for today but was significantly heavier than expected, and timing during rush hour made conditions worse. "

In the past 10 days Transport Scotland have spread approximately 50,000 tonnes of salt throughout the country.