Crisis talks are being held to prevent the UK being cut off from the continent over fears about the spread of the new coronavirus variant.

French transport minister Jean-Baptiste Djebarri said he hoped a protocol would be agreed by European Union states “to ensure that movement from the UK can resume” after his country banned passengers and freight crossing the English Channel.

Boris Johnson was chairing a meeting of the Cobra emergency committee to discuss the mutant coronavirus and the travel restrictions imposed by the French and a string of other countries in Europe and beyond.

The closure of cross-channel routes until at least Wednesday has alarmed businesses in the lead-up to Christmas and with the added complication of the end of the Brexit transition period on December 31.

Sainsbury’s warned that disruption could hit supplies of lettuce, some salad leaves, cauliflowers, broccoli and citrus fruit, all of which are imported from the continent at this time of year.

Mr Djebarri said there would be a “solid health protocol” to “protect our nationals and our fellow citizens” while allowing movement to resume.

Measures being considered in France include the possibility of testing the country’s nationals to allow them to return from the UK.

Transport Secretary Grant Shapps said emergency measures were being put in place to cope with a backlog of lorries heading for the Channel ports.

But he sought to play down the potential impact, stressing that container freight was not hit by the ban on people crossing the border and hauliers were “quite used to anticipating disruption”.

The disused Manston Airport in Kent would be used as a lorry park, while Operation Stack, the contingency measures used to queue on the M20 whenever there is disruption at the channel, was already in place.

The Transport Secretary dismissed concerns about the impact of the travel ban on supplies of the Pfizer/BioNTech vaccine, which is manufactured in Belgium, because container freight was unaffected.

The chief executive of the Road Haulage Association (RHA), Richard Burnett, said the disruption could cause problems with “fresh food supply” in the run-up to Christmas.

He told BBC Radio 4’s Today programme: “With it being so close to Christmas we’re looking at 48 hours at this point in time in terms of the restrictions, we’re likely to see Operation Stack building in terms of numbers of vehicles on the UK side and that might be a deterrent for EU hauliers to want to come so close to Christmas and end up being stranded here, that’s part of the challenge that we’re facing today.”

Port of Dover chief executive Doug Bannister told the PA news agency that a prolonged period of disruption would be a “stark situation”.

“Because of the importance of the Dover straits in handling critical goods such as food and other things like that I think it could become quite dramatic,” he warned.

Mr Johnson faced demands to recall Parliament to address the crisis, which follows the introduction of a new Tier 4 level of lockdown on London and large parts of south-east England.

Concerns about the spread of the new variant also led to the dramatic scaling back of Christmas plans, with mixing banned in Tier 4 and the three-household provision being allowed for just Christmas Day itself in the rest of England.

Mr Johnson will lead a Downing Street press conference on Monday to set out the latest developments.

Meanwhile:

– Cases of the new variant have been reported in Iceland, Denmark, the Netherlands, Gibraltar and Australia.

– Official figures indicated Wales has had more than 600 cases of the new coronavirus but this is “almost certainly a significant underestimation”, First Minister Mark Drakeford said.

– Experts warned that social distancing measures would have to remain in place until around 50% of the population had been vaccinated, a process which could take months.

– Analysis by PA found that, of the 127 acute hospital trusts with a 24-hour (type 1) A&E department in England, 42 (33%) had more Covid-19 patients on December 18 than at the peak of the first wave in the spring.

The U-turn over Christmas plans and the imposition of the Tier 4 lockdown on almost a third of England’s population has led to pressure on the Prime Minister from his own benches.

Conservative former minister Sir Desmond Swayne questioned the timing of the Government’s announcements.

“They’ve been looking at it since September, and how convenient when Parliament went into recess on Thursday, suddenly they were then able to produce this revelation,” he told the Today programme.

“Let’s see the evidence then, let’s have Parliament back and show us and convince us – come clean.”

Among the authorities imposing travel restrictions on passengers from the UK are: France, Ireland, the Netherlands, Belgium, Italy, Austria, Bulgaria, the Czech Republic, Slovakia, Denmark, El Salvador, Turkey, Canada and Hong Kong.

They reacted after Mr Johnson announced that the new variant was up to 70% more transmissible than the original strain, while Health Secretary Matt Hancock admitted it was “out of control” and the Tier 4 lockdown may have to remain in place for months.

Stephen Evans, professor of pharmacoepidemiology at the London School of Hygiene and Tropical Medicine, said vaccination alone will not be enough to bring the virus circulating in the community to “very low levels” so restrictions “are going to need to be carried on”.