French computer problems have wreaked havoc on Eurostar travel services for tourists who want to escape for the long weekend.
Problems with France’s automated border gates at St Pancras station forced thousands of passengers to queue on a line meandering through the streets of London.
Officials said the electronic gates had been affected by software problems, which delayed immigration checks in the UK before departure.
Eurostar said: “Today our stations are very busy. Passport and security checks are taking longer than usual due to problems with the control systems of the French authorities.”
Queues are accumulating more misery for mid-term holidaymakers, many of whom will have hoped to avoid the widespread disruption seen at airports in recent days.
Problems with electronic gates also caused disruptions in Paris for people returning to the UK and French airports.
Author Svenja O’Donnell said she had been waiting in line for almost three hours to catch a train to Paris.
She said: “The queue goes through the whole station and goes down two islands.
“We have been given very little information.”
It was also reported that at least one Eurostar train left without the on-board toilets working.
A Eurostar spokesman said: “Unfortunately, we had a technical breakdown on a train in the early hours of the morning, which meant we had to take it out of service.
“As a result, there are delays of 30 to 60 minutes on departure to London St Pancras.
“The queues are moving and our staff is working hard to take care of the passengers and make sure check-in is as easy as possible.”
Eurostar trains were delayed by about 30 minutes, the spokesman added.
The computer error was fixed shortly after lunchtime, Eurostar added.
Chaos followed at St Pancras on Tuesday after a crash on one of the Eurostar trains. Angry passengers used social media to unwind in the face of an “absolute basket”.
One passenger said, “Thousands of people, queuing up at the station, going out and coming back. Shocking mismanagement.”