Striking ferry workers in the French port of Calais have agreed to let some ships through in a partial lift of a three-day-old blockade.
Unions representing MyFerryLink workers are trying to prevent massive job cuts following the sale of the company earlier in June 2015 to Danish rival DFDS.
The easing of the blockade, which has caused chaos on both sides of the English Channel, comes after French transport ministry officials agreed to meet union representatives.
"We've accepted to lift the blockade of the port from 7pm [on 1 July] to let P&0 boats through one by one," union official Eric Vercoutre told journalists.
More than 3,000 migrants are thought to be at the docks and are trying to take advantage of the chaos to get across the Channel.
Adam, 36, a migrant from war-torn Darfur region, told Reuters: "I am from the Zaghawa ethnic group and I no longer have a future in Sudan, although I have graduated. I have been in France for the last two months and our life these days is very difficult. I hope to arrive to the UK because I will have identification documents quicker than in France."
The strike action coincides with the end of the school year, when many families will be trying to make their way to Continental Europe through the French port.
Kent Police said that M20 have closed junctions 8 (Hollingbourne) and 9 (Ashford West) and London bound between junctions 9 and 8 to implement phase three of Operation Stack.
Non-freight traffic continues to be diverted onto the A20 in both directions. "This allows backed-up lorries to park on both the coast-bound and London-bound carriageways of the M20," Kent Police said.
Operation Stack allows parts of M20 to be used as a staging area for goods vehicles headed for the continent to queue to avoid gridlock across Kent's road network.
Kent County Council has arranged for water to be distributed to lorry drivers affected and portable toilets are in place along the M20.