The worst delays occurred during Saturday as France border officials based in Dover began operating at “a heightened level of security”.

Travellers using the port were told to take “plenty of food and water” to cope with the delays, which began building up on Friday.

Port of Dover said that the “exceptional security situation” had been made worse on Saturday morning by French border control booths being “seriously understaffed overnight with only three booths available for tourists out of a potential seven”.

“At one stage, only one French officer was available to check passengers on hundreds of coaches, resulting in each coach taking 40 minutes to process,” said the port in a statement.

“The Port of Dover, which has no authority over French border operations, raised concerns over French manning levels with the UK government earlier this week and the government, in turn, raised the issue with its French counterparts.”

The problem eased over the course of Sunday with queues being reduced to around one hour and the port said that the roads were clear by early Monday morning.

“The port is expected to be busy throughout the day (Monday) so please allow plenty of time for French border checks prior to check-in,” said the port in its latest travel update.