Flights to Gatwick and Luton had to be diverted as snow and ice made runways unsafe.

Weather experts have warned there is more snow on the way, with blizzards and wintry showers expected over the weekend.

Police today urged motorists not to drive unless the trip was essential after heavy snow forced numerous road closures and left others barely passable.

A spokeswoman said: “Only go out if absolutely necessary. If you do go out, be well equipped.”

Southern counties of England appeared to be the worst hit, with a series of jack-knifed lorries adding to the chaos.

In Essex, more than 70 lorries got stuck in blizzards on the A120 near the port of Harwich, and on the A12 near Colchester some drivers had to sleep in their vehicles until gritters and snowploughs reached them.

In Kent, lorries and cars were said to be stranded in several parts of the county, with roads in Medway in particular said to be in “poor condition”, a police spokeswoman said.

In Kent this afternoon, the coastbound M20 was experiencing severe congestion between Junctions 3 and 7, but the London-bound carriageways were free flowing.

The M2 was clear of incidents, the A21 was open but slow moving but the A2 was partially closed at Watling Hill, a Kent Police spokesman said.

Mr Nix said: “Driving conditions are hazardous so please do not travel unless your journey is absolutely necessary.

“The snow is heavy in Maidstone, Medway, Tunbridge Wells and in North Kent.

A major road in Northamptonshire was brought to a standstill by the snowy conditions.

Motorists were advised to avoid the A14 after both westbound and eastbound carriageways were blocked by vehicles which had either broken down or been involved in minor collisions.

Five lorries were also stuck in a dip on the A509 between Wellingborough and Kettering, which was later cleared.

Air delays

Heavy snowfall led Gatwick airport to be shut from 12.15am until 7.33am today. Budget airline easyJet was one of the carriers affected and it cancelled all flights at Gatwick until 11.30am. Even when Gatwick re-opened there were delays and diversions to flights.

Luton airport in Bedfordshire was shut until 10am, with easyJet again among the suffering airlines, cancelling all flights until 11.30am. The two other main London airports – Heathrow and Stansted – stayed open, but there were delays to flights, as there were also at Manchester airport.

EasyJet said that it had had to cancel around 50 flights at Gatwick, Stansted and Luton today.

A spokesman for Heathrow Airport said the runways have been cleared through the night.

“Heathrow is open for business as usual,” he said.

Passengers are advised to check with their airline before leaving for the flight, he added.

Rail holdups

Overrunning engineering work which led to buses replacing trains between Gloucester and Newport in South Wales added to rail passengers’ problems today.

Services between Milton Keynes in Buckinghamshire and Watford Junction in Hertfordshire were also affected and there were delays to services in and out of Stansted airport station.

There were no services for a time between Tonbridge in Kent and Redhill in Surrey, while signalling problems led to disruption near Hemel Hempstead in Hertfordshire.

Services on the London to Paris and Brussels high-speed Eurostar trains, where drivers started a pay strike today, were slowed by the terrible weather in Kent.