The Armed Forces are helping to administer COVID-19 tests to lorry drivers stuck in Kent, waiting to cross the English Channel to France.
It comes after the French government put in place a travel ban in response to fears over the transmission of the more infectious coronavirus strain which is spreading in the UK.
France lifted the ban on Wednesday but said those looking to enter from the UK must have received a negative coronavirus test taken less than 72 hours before their journey.
It is understood 170 military personnel, including soldiers from 36 Engineer Regiment and 1 Irish Guards, are working alongside civilians and NHS Test and Trace staff to test the thousands of stranded drivers.
Lieutenant Patrick Burford, from 36 Engineer Regiment and the Queen’s Gurkha Engineers, spoke to Forces News on Wednesday evening, as the testing commenced.
He explained they arrived in Kent at 14:00 on the day to "get a feel of what was happening" and "liaise with the civilian agencies" who run the Test and Trace programme.
"We've started to implement our own systems in place and things are starting to get moving now as more and more test results are coming through," Lt Burford said.
"The NHS Track and Trace system are the leads for the testing itself and we are kind of learning from them and learning the process of how best to implement the testing programme."
The tests that the military are helping to administer "can give a result within 30 minutes" and allow testers to understand "very easily" if they are positive or negative, Lt Burford added.
WATCH: Lt Burford speaks to Forces News.
On Wednesday morning, the Department for Transport confirmed the testing process had started.
However, thousands of lorry drivers are likely to spend Christmas stranded in Kent as the Government has indicated queues will not start to move for at least another 24 hours.
Transport Secretary Grant Shapps said the lorries – about 6,000 at one point – some of which have been parked on the A2 since Sunday, will begin moving on Christmas Day, as French firefighters and the British military work with NHS Test and Trace to continue the testing process.
Mr Shapps also said France and the UK had agreed to keep the border open at Dover, the Eurotunnel and Calais "throughout Christmas" to get citizens and hauliers cleared "as soon as possible".
He promised ferries will sail on Christmas Day and Boxing Day, as 26 French firefighters brought 10,000 extra tests to the port on Thursday to help speed up the process.
The Road Haulage Association (RHA) confirmed that all drivers, regardless of nationality, will be required to be tested.
If the drivers test positive for COVID, they will then have a PCR test, and those who return a second positive result will be offered "COVID-secure" accommodation.
A disused airfield at Manston has become the main testing centre for hauliers, with drivers required to self-administer swabs in their cabs under supervision.
Since Sunday lorries had been held in three traffic management operations in Kent – in Operation Stack on the M20, in Operation Brock and about 4,000 vehicles were at Manston lorry park – in an attempt to stop the county's roads getting gridlocked.
There were reports of disturbances at Dover and at the lorry holding facility in Manston involving those waiting to cross the Channel on Wednesday morning, Kent Police said.
Footage showed a handful of officers attempting to push back a crowd of protesting drivers in Dover.
About 1,400 military personnel are currently deployed on more than 50 COVID-19 tasks to support the UK's response to the coronavirus pandemic.