Hundreds of seats are purposefully being left empty on Eurostar trains as the cross-Channel operator struggles to process post-Brexit passport checks.
Processing times have risen by at least 30 per cent at train stations that were designed for intra-EU travel.
Trains are carrying 30 per cent fewer passengers as a result.
By reducing the number of tickets on sale, Eurostar staff are lowering the number of passport checks that need to be completed before trains depart, rather than failing to process passports for full-capacity trains on time and delaying services.
UK passengers travelling to the European Union (EU) need to have their passport stamped when they cross the border, which is causing delays.
New technology to replace these checks has reportedly been delayed and isn’t expected to rollout until the end of the year.
Chief commercial officer Francois Le Doze more seats can be filled later in the day.
Eurostar has already reduced the number of trains between London and Paris from 18 to 14 per day.
Speaking to reporters in Brussels, Ms Cazenave, who began her role in October last year, said: “We cannot offer enough seats because of this bottleneck at stations.”
It is vital that the first departures of the day are on time to avoid a knock-on impact, she explained.
“If you delay the first train, then you delay the second and then it’s a very bad customer experience.
“Our customers say it’s awful.”
Passengers are being asked to arrive up to 90 minutes ahead of departure to ensure they have time to pass through border checks, which is three times longer than before the pandemic.
Ms Cazenave revealed that the disruption means it is unlikely the operator will resume selling tickets for skiers travelling between London and the Alps in the short-term.
She said: “As long as we do not are not able to operate as well as possible from a customer experience standpoint in London and Paris, why should we go to Bourg-Saint-Maurice 10 times a year?
“Our main focus now is about fixing this major issue and then we’ll think about what we do in the coming years for these kind of destinations.”
The issue at stations is not “impossible to tackle”, Ms Cazenave insisted.
“We have to be better organised. We have to have more staff from the police. We have to automize more than before.”
Eurostar Group, created following a merger between Eurostar and Thalys – which runs rail services in continental Europe – announced on Tuesday all its trains will operate under the Eurostar brand from later this year.
It is hoped this will lead to smoother ticket-buying and shorter connections for UK passengers travelling between London and German destinations including Cologne and Frankfurt.
A new logo inspired by the North Star was also unveiled, which is a “tribute” to Eurostar’s first symbol when it was created in 1994.
Ms Cazenave said: “Our customers will be able to experience the same quality of service they know and love across our unified network, linking iconic business and leisure destinations across five European countries.
“As Eurostar Group we are in a unique position to spark the next chapter for rail travel, to truly drive the modal shift from road and air to rail.”