DRIVERS were urged not to use major roads in parts of Scotland in the wake of a fresh forecast of heavy snow overnight.

Police issued their highest level travel warning for parts of South Lanarkshire and Dumfries and Galloway, saying motorists should stay off the roads unless absolutely necessary until at least 5am today.

The advice came after more than 200 people were left stranded when icy blizzards brought a section of the M74 to a standstill on Tuesday night and into yesterday morning.

Scotland’s Transport Minister Humza Yousaf told MSPs at Holyrood that following a new Met Office amber warning for Wednesday evening, Police Scotland were upgrading their travel warning from stage three to a stage four.

He said: “First, I apologise to road users who were stuck on the M74 last night. It is not a situation anyone should have to experience and that is why we are taking steps to make sure we don’t face similar issues tonight.

“After speaking with all of our partner organisations, the police have decided to raise the travel warning to stage four, which means you should avoid travel in the affected area during the period of the amber warning.

“This decision has not been taken lightly, but it is the safest course of action. We don’t want people to travel during this period and put themselves and others at risk.”

He added: “That, in practice, means that all travel should be avoided on those parts of the trunk road affected by the amber warning, namely south and south-west Scotland for the duration of the amber warning.”

Police Scotland closed parts of the M74 in Lanarkshire in both directions due to wintry conditions for a number of hours, and mountain rescue teams were drafted in to check on drivers, many of whom were stuck in their vehicles.

Police declared the situation a critical incident, although the road later reopened at daybreak.

The Met Office amber warning advises that travel disruption is likely, with a risk that some vehicles may be stranded.

The warning, which ran from 9pm last night until 5am today, said that 3cm-8cm of fresh snow was likely to accumulate widely, with up to 20cm over high ground.

Yellow “be aware” warnings of snow and ice for much of the country are valid until tomorrow.

The heavy snow across the country brought widespread disruption yesterday, with an estimated 40,000 children missing classes as around 300 schools shut across Scotland.

All schools in the Borders were closed due to the weather while 16 secondary schools, 58 primaries and 44 nurseries in the Highlands were shut.

About 20 schools in Dumfries and Galloway and 28 schools and nurseries in South Lanarkshire were also closed.

All prelim exams scheduled to take place in North Lanarkshire secondary schools today have also been postponed.

Elsewhere a runaway lorry slid down a snowy street then crashed into a fence on Tuesday morning in Glenmavis, North Lanarkshire.

Witness Niki Blackhall, who filmed the incident, said: “The men in the truck got out to help the crashed cars and the truck slid away. It hit our wall. I’m just glad nobody was injured and the wall stopped the truck from sliding down the hill, as the outcome would have been a lot worse.”

Public Health England issued cold weather alerts and health warnings in light of the cold weather, urging people to take extra care.

Head of Road Policing north of the Border, Chief Superintendent Stewart Carle, said: “Weather conditions over the last few days have been extremely challenging, and this forecast of even more extreme conditions over the next day or so in these areas mean that we have to advise drivers to avoid travelling, and if they do, to expect severe delays of several hours or more.

“We urge people to think very seriously as to whether their journey is really necessary and is worth the risk, and if they decide they really have to travel, to be fully prepared to be self-resilient. If you need medication, for example, ensure you have it with you.

“No-one should ever place themselves at risk on the road.”