The chairman of Tesco has warned of short-term fresh food shortages after the Brexit transition period concludes at the end of the year.
John Allan said: "We can’t rule out the possibility that if there is dislocation at the ports of entry to the UK there will be some shortages of some items of fresh food, at least for a short time."
Speaking to Bloomberg TV, he added that there is no need for consumers to panic or stockpile items as any disruption will "normalise quickly".
"The nation’s supply chain for food will continue but there may be some things we have to learn to live without for a few weeks, possibly a few months," he said.
There are concerns that trade deal negotiations between the the UK and the EU have lost momentum.
Last night David Frost, the UK's chief negotiator, accused the bloc of dropping a commitment to intensify negotiations before its deadline of the end of the month.
However, Foreign Secretary Dominic Raab suggested on Thursday that Boris Johnson will continue negotiations despite his no deal deadline of Oct 15 being missed.
Tesco's chairman said disruption to supply chains in January would come at the "worst possible time for the food industry".
The end of the transition period will follow the supermarket industry's busy Christmas period when there is "very little spare capacity to build stock", Mr Allan said.
Grocers are working to create "maximum possible inventory" to mitigate any possible disruption.
Supermarkets have benefited from the pandemic in recent months as the prolonged closure of the hospitality industry forced Britons to eat at home more often.
Tesco reported a surge in interim profits last week. New boss Ken Murphy said he aimed to keep Britain’s biggest supermarket "focused".
According to the British Retail Consortium, around four-fifths of imported food sold in UK supermarkets comes from the EU.