Ongoing talks with France to reopen full trade and transport across the Channel need to be resolved today in order to avoid severe disruption, an industry expert has warned.

Andrew Opie, director of food and sustainability at the British Retail Consortium, said the “borders really need to be running pretty much freely from tomorrow” or supplies of fresh produce like “salad, vegetables, fresh fruit” won’t reach shelves in time.

“The problem actually is empty lorries, so the empty lorries which are now stuck in Kent, they need to get back to places like Spain to pick up the net (next) consignment of raspberries and strawberries and they need to get back within the next day or so otherwise we will see disruption,” he told the BBC Radio 4’s Today programme.

“As long as it can be cleared today there’ll be minimal impact for consumers – remember the shops are shut on Christmas Day which takes one day of buying out of the equation, but those lorries that are stuck in Kent, they do need to get back within the next day.”

Supermarket giant Sainsbury’s warned that disruption in Kent could hit supplies of lettuce, some salad leaves, cauliflowers, broccoli and citrus fruit, all of which are imported from mainland Europe in the winter.

There are currently 650 lorries on the M20 as of 6am and 873 have been moved to a temporary holding area at Manston airfield.

Royal Mail has suspended almost all of its mail services to Europe due to “coronavirus transport impacts” and DHL warned that a number of its parcel services would also be suspended in the UK. 

Last night Boris Johnson said at a Downing Street press briefing the number of lorries waiting on the M20 had been reduced from 500 to 170, but Highways England later said Kent Police had told them there were 900 lorries parked on the motorway as of 6pm on Monday.

Home secretary Priti Patel said the government was “working to get a resolution” as talks continued with France on reopening full trade and transport across the Channel.

She told Sky News: “We speak to our colleagues in France constantly on a range of issues and that work has been under way over the last 24 hours and will continue today.”

The BBC reported plans to reopen the border will come into effect from Wednesday, citing French Europe Minister Clement Beaune.

The scramble to reopen the UK’s links with Europe comes after countries around the world closed off air and transport corridors over fears of a mutant strain of coronavirus sweeping across London and the south east of England.

The new variant of the virus led the to government effectively cancel Christmas for millions of people with strict new tier 4 restrictions across these areas.

Speaking at a Downing Street press conference on Monday, chief scientific officer Patrick Vallance said more tier 4 lockdowns are “likely” as the new and more infectious strain of Covid-19 means the virus “will spread more”.

Scientists estimate the new variant, which first emerged in Kent, is up to 70% more infectious.

“Evidence of this virus is it spreads easily, it’s more transmissible,” Vallance said.

“We absolutely need to make sure we have the right level of restrictions in place. 

“I think it is likely that this will grow in numbers of the variant across the country and I think it’s likely therefore that measures need to be increased in some places in due course, not reduced. 

“It is the case that this will spread more.”