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Frustrated families were fighting with each other in "absolute bedlam" while being forced to wait as long as eight hours to board ferries.
Holiday makers hoping to return to Kent through the Port of Calais said they had to endure lengthy delays at British border control.
Shipping company DFDS, which runs ferries between the port and Dover, tweeted to say there was a delay of at least three hours at around 1am today.
An update from P&O Ferries on Twitter at 7.30am warned there are still delays this morning.
A spokesman said: "Please be advised there are currently large queues at UK Border Force and check in.
"Rest assured you will be on the next available crossing if you miss yours."
A number of families have spoken out to say that hey have been waiting far longer than three hours with no explanation.
Mum of two Nicki Evans told KentOnline that she saw people fighting with each other during her family's wait of almost seven hours
"We arrived at Calais at 6pm for our 7.05pm ferry, we eventually set sail at 02.40am," she said.
"It was absolute bedlam, people fighting and arguing with each, as cars were just pushing in front of others.
"There was not queuing system. There was no staff coordinating or communicating with passengers. The only time staff were visible was when people started kicking off with each other.
"There were toilet facilities however there was just one vending machine which was completely empty, so there was no food or drink.
"We were travelling with teenagers, but some families had young children and babies, who were seen agitated and crying. We were bumper to bumper the whole time.
"I really couldn't understand what the problem was. It was quite honestly carnage!"
"Absolutely no sign of border staff until people actually started fighting and no explanation from staff to how long the delay would be or why."
This is the second major cross-channel issue in as many days, after a broken-down Eurotunnel train caused chaos yesterday.
Passengers were forced to disembark – leaving 100 vehicles behind – and walk to a passenger transport.
Numerous people reported being stuck on the affected train for almost five hours, citing issues with the replacement train.