BBCHundreds of Eurostar passengers are being held up at Gare du Nord in Paris due to technical delays.
Eurostar said in a statement that a problem with UK Border Force e-gates had caused the delays.
“We are sincerely sorry for the inconvenience caused,” the company said, advising customers to delay their journeys to London if possible.
Hundreds of people were waiting at the station on Thursday afternoon, many of them families with young children on their half-term break.
The BBC’s Roopa Suchak was at the station with her family – including her husband, 10-year-old daughter, and her sister-in-law and her two children aged six and 10.
She said passengers had been warned to expect two-hour delays.
When asked to describe the scene at the station, Ms Suchak said simply: “It’s mental.”
“We arrived here two hours before departure and we’ve only just been allowed to join a queue of about 300 people trying to get up to the immigration desk, so we’re nowhere near there yet.
“There are large groups of people with lots of kids coming back from Disney because of half term. Everyone’s quite frustrated, quite tired, and they’re not quite sure what to do.”
Also waiting in the queue to passport control was Kesha Hancock from Hertfordshire. She was returning to London with her husband Krys and their 10-year-old daughter, Hollie.
She told the BBC that the ordeal was a less-than-ideal end to a lovely and relaxing break.
“This is the second time we have been to France in two years. The last time was on the ferry and this feels like déjà vu. I can’t help thinking that Brexit is the problem,” she said.
Another person hoping to get back to London is Lizanne O’Connor from Surrey, who described the scene as “slightly chaotic”.
“More information and clarity would be good,” she said, adding that she was travelling with her grandparents and children who had not been offered water.
“They keep repeating the same information!”
Dhruti Cramer, from Ohio in the US, told the BBC that despite the stressful situation most people, including staff, were remaining calm.
“If my children were younger, things would be more difficult!”
Eurostar said: “A technical problem is affecting the UK Border Forces e-gates at Gare du Nord, which is causing major delays on trains to London.
“We are awaiting the intervention of a technician to resolve this problem as quickly as possible and reduce the impact on our passengers.
“Eurostar teams are taking all measures to make sure that those who need to travel will be able to arrive in London.
“We advise those who can, to postpone their journey. We are offering affected customers exchanges free of charge or a full refund of their journey.
“We are sincerely sorry for the inconvenience caused.”
