Some posters seem determined to whip up panic. From the BBC website:
Freight industry lobby group Logistics UK appealed for calm from shoppers, and said it was "maintaining close contact with UK government to ensure that supplies of fresh produce are available throughout Christmas and the new year".
Although freight from France is still allowed to enter Britain, there are fears lorry drivers might not travel because they fear being stuck in the UK over Christmas.
Unaccompanied freight, such as containers or lorry trailers on their own, can still be transported.