Rail, air and sea services between the UK and France are resuming this morning after the French government agreed to ease its travel ban over Covid fears.
French citizens, British nationals living in France and hauliers are among those now able to travel - if they have a recent negative test.
Soldiers have joined NHS Test and Trace staff in Kent to carry out rapid tests on stranded lorry drivers.
Thousands of vehicles have been stuck there since the border shut on Sunday, reports the BBC.
Despite France and UK reaching an agreement, more than 50 other countries, including Italy, India and Pakistan, are continuing to block travellers from the UK.
Foreign governments acted after the UK government introduced strict tier four - "stay at home" - restrictions across large parts of southern and eastern England in response to a new variant of coronavirus.
Under the agreement between the UK and France, those travelling for urgent reasons, including hauliers, French citizens, and British citizens with French residency will be allowed into France.
But in order to travel, they will need to have received a negative test result less than 72 hours before departure.
The Netherlands announced it would allow UK arrivals again, as long as they have a recent negative result.
However, the decisions may come too late for some French and Dutch nationals living in the UK to secure tests in time to get home for Christmas.
It comes as:
- A "gold command" meeting of ministers and officials considers extending tier four curbs to more parts of England - with changes coming as early as Boxing Day. Sources say places immediately surrounding current tier four areas, largely in southern England, could soon be placed under the toughest restrictions
- A further 17 areas in England - from Lincolnshire to Bristol - receive access to rapid mass community testing in the coming weeks to help slow the spread of the virus
- Scotland's First Minister Nicola Sturgeon says "I'm kicking myself" after a photograph shows her breaking Covid rules
- And rationing is implemented at the UK's biggest grocer, Tesco, in a bid to maintain supplies
Eurotunnel said freight services between the UK and France would resume at 07:00 GMT.
The Channel is a vital trade route, with about 10,000 lorries a day travelling between Dover and Calais at Christmas, largely bringing in the freshest produce.
Supermarkets have been warning that the travel ban and subsequent delays at ports could see shortages of certain fresh foods, including lettuces and citrus fruits coming from the Continent.
Under the new agreement with France, rapid "lateral flow" tests will be used, which can detect the new variant and work like a pregnancy test to give a result in about 30 minutes.
Freight drivers will receive their test result by text, and that message gives them the right to cross the Channel.
Testing will also take place on the French side for hauliers entering the UK.
A "protocol is still being finalised" to work out what to do with those drivers who test positive, a government source told the BBC.
The Netherlands has demanded UK arrivals use so-called PCR tests, which can take over 24 hours to turn around as they require a lab.
Elizabeth de Jong, policy director at business group Logistics UK, said its members were "relieved" to hear the border had reopened.
But she urged officials to set up Covid testing procedures quickly "to ensure divers can be processed and get home for Christmas safely".
The Road Haulage Association said: "Even if the border is opened up, a short delay in the process is going to mean huge delays in the supply chain."
Despite the easing of restrictions, UK Transport Secretary Grant Shapps warned hauliers against travelling to Kent until further notice to help alleviate congestion at its ports.
Earlier, the European Commission urged other EU member states to lift travel bans affecting the UK - but said non-essential travel should be discouraged.
A further 36,804 people in the UK have tested positive for coronavirus and there were 691 deaths within 28 days of a positive test, according to Tuesday's government figures.
It is the largest daily number of cases recorded yet, though it is thought the infection rate was higher during the first peak in spring when testing was much more limited.
