The AA is warning of the dangers of driving with snow on the roof of the car. President Edmund King says:
"Drivers must clear the snow off their windscreens, lights and tops of their cars before setting out.
This morning we have spotted lots of 'snowman cars', which are cars driving along with piles of snow on their tops. I saw one sports car this morning on the M3 with almost a snowman of its roof but the dangerous thing was that it was being followed by a motorcycle.
The hardened snow could have been a real hazard, had it fallen off in the path of the motorcycle. We have also seen drivers peering out of small openings on their windscreen as if they were driving a tank.
The other issue is the number of cars with their lights and indicators compacted with hardened snow. Drivers need to take a broom to clear excess snow off their vehicles before setting out."
One hundred flights have been cancelled at Heathrow so far today amid reports that the hub airport is like a "refugee camp".
Drivers are advised to avoid the roads in snowy weather, but here is some advice from the AA on journeys that are unavoidable.