Travellers heading towards France could face traffic delays for several weeks, police have warned, as UK officials assist French border staff to help ease congestion.
The combination of new security checks and a holiday exodus caused "extraordinary" tailbacks this weekend amid soaring temperatures.
Drivers who have been stranded in Dover for almost a day say the situation is getting "desperate".
One man, who said he had been stuck for 19 hours, posted a picture of his young granddaughter, who he said had become "weak and dehydrated" as the nearest place to buy water was a three-mile walk away.
Meanwhile, University of Bolton graduate Anita Klipanovic - who had been on her way to a week's holiday in Croatia - said she had been stuck in the queue for 13 hours.
Hundreds of motorists were forced to spend the night in their cars as increased security checks by French border control in the wake of recent terror threats caused lengthy delays.
New security checks for travellers heading to France cause tailbacks of up to 20 hours for some.
As police warn disruption at Dover is set to continue, volunteers who came to the aid of stranded motorists offer further assistance.
Holidaymakers heading to the continent face ten hour delays as France has stepped up its security checks in the wake of the terror threat.