More than 2,000 people spent the night trapped inside the Channel Tunnel after four Eurostar trains broke down due to wintry weather.
It is thought the trains failed as they left the cold air in northern France and entered the warmer air inside the tunnel, Eurostar spokesman Bram Smets said.
The exhausted passengers are now on their way home, hours later than expected, but the tunnel remains closed.
Hundreds of people are stuck in France waiting for services to resume and many others are waiting in Folkestone.
Anyone with tickets for crossings today has been asked to postpone their trip unless it is absolutely necessary.
The tunnel closure had added to travel problems caused by heavy snow in Kent and police have brought in Operation Stack – which allows lorries to park along sections of the M20 – to ease congestion near the terminal.
Two of the stranded trains have been moved from the tunnel and are being pushed to London St Pancras by diesel locomotives.
Passengers from a third were evacuated from the stricken train by Eurotunnel shuttle and later transferred to a Eurostar train bound for St Pancras.
Hundreds of people on the fourth train were taken by shuttle to the terminal in France.
A second shuttle will bring them back to Folkestone where they will transfer to a London-bound Eurostar.
More snow is expected across the UK today and overnight.
Helen Rossington, forecaster with MeteoGroup UK, the weather arm of the Press Association, said light snow showers were expected in eastern coastal areas.
A band of snow over Scotland will move south, reaching northern England today.
The North East and Yorkshire could see between 10 and 15cms of snow on high ground, she said.
Snow will reach southern England tonight with eastern areas likely to see between two and 5cms.
The Port of Dover later said that the French authorities were allowing tourist traffic only to disembark and ships were now sailing from Dover. However, freight was still restricted.
A Port of Dover spokesman said: “The port is still full and traffic continues to queue on the A20 into Dover.
“Customers intending to sail to Calais are advised not to set out for the port without checking with their operator first.”
Budget airline easyJet said it expected continued disruption to flights today.
Passengers were advised to check the airline’s website before setting off for the airport.
If their flight is cancelled, the airline suggests they arrange a refund or reschedule their flight online rather than travelling to the airport.
A spokesman said: “Passengers should be aware, given this is a busy time of year, there is little availability over the next few days, so passengers whose flights have been cancelled today may not be able to transfer on to flights for a few days.”