France has banned hauliers carrying freight across the Channel from the UK for 48 hours after a new coronavirus strain was detected in the southeast of England.
The move was an attempt to stop the highly contagious COVID variant from reaching the European mainland.
Thousands of lorries that were meant to travel via the Channel on Monday have been told to stay away from Kent ports.
HGVs turning up at Dover have been greeted with signs saying "French borders closed" and are being turned away.
Sky News looks into what France's decision means for companies and consumers in the days before Christmas after the ban was imposed on Sunday night.
Are all British ports affected?
No. As the ban is just on road haulage and not container ships, it only affects products going out on lorries - but it could also affect those coming in.
Andrew Opie, the British Retail Consortium's director of food, said that although lorries are allowed into the UK, it may be that haulage firms will be unwilling to send trucks and drivers across to the UK without a guarantee they can return to the EU in a timely manner.
Dover and Portsmouth are both affected as lorries come across from France into those ports. Some 10,000 trucks cross between Dover and Calais each day.
Folkestone, where the Channel Tunnel comes into, is also affected.
But France's transport minister Jean-Baptiste Djebbari has said there is a plan to establish a European-wide mechanism to allow traffic flows with Britain to resume in the coming hours.
What kind of products are imported and exported through those ports?
Transport Secretary Grant Shapps said 20% of the UK's daily imports come via Dover and Folkestone.
But, it is the nature of those products that is causing concern as the majority are perishable goods.
Paul Mummery, spokesman for the Road Haulage Association (RHA), told Sky News: "It's roll on roll off, trucks with 'just-in-time' products, perishable goods.
"It's the biggest issue for the most perishable goods such as veg which have a short shelf life."
At this time of year, products such as lettuce, salad leaves, cauliflower, broccoli and citrus fruit all come from the continent.
Also, fresh seafood is a major British export through those ports, especially at this time of year, and with a short shelf life there is a risk it goes to ruin.
Will there be food shortages?
The RHA and the government is urging people not to panic buy as the UK supply chain is very well stocked at this time of year.
It is even better supplied than usual as supermarkets prepare for a potential no-deal Brexit on 1 January.
"We are urging people not to panic buy because the supply chain is resilient," the RHA's Mr Mummery said.
"There is plenty of stuff to go around at the moment, there will be plenty of toilet roll, pasta, flour - as long as people do not panic buy.
"If this goes beyond 48 hours it will be more of an issue."
Sainsbury's has warned there could be "gaps over the coming days" in the supply of lettuce, some salad leaves, cauliflowers, broccoli and citrus fruit.
But, the supermarket said all products for the "great British Christmas lunch" are already in the country and they are very well stocked.
The British Retail Consortium added that there was no need to panic buy for the festive period as most of the traditional Christmas lunch is from the UK, or has already been imported.
How will this affect British exports?
Scottish seafood exporter Lochfyne said it was a "disaster" for them as they already have "millions of pounds of seafood" on its way to ports.
A spokesman said: "Even if we get through 48 hours later, we will miss the Christmas deadline, this is unbelievable."
Other routes into the EU, via Belgium or the Netherlands, could be used by hauliers.
"However, this does mean if they're delivering to France the end shelf life is shorter as it will take longer to get there," Mr Mummery said.
"We don't think they will, but lorries could be stopped at France's borders with other countries."
