Thousands of travellers are embarking on trips to France ahead of the introduction of a ban on UK tourists.
Cross-Channel rail operator Eurostar is urging people to avoid London St Pancras station unless they have a pre-booked ticket and a negative coronavirus test result.
Most of the firm’s train services on Friday were sold out as many people brought their Christmas travel plans forward after the new restrictions were announced on Thursday.
Ferry operators and airlines have also experienced a surge in demand.
French Prime Minister Jean Castex said tough restrictions will be enforced from 11pm UK time on Friday, including a requirement for “compelling reasons” to travel to or from the UK.
Trips for tourism or business will not be permitted.
Mr Castex’s office said this is “in the face of the extremely rapid spread of the Omicron variant in the United Kingdom”.
People intending to travel through France to other countries can only continue with their trip if they are remaining in the international area of an airport for under 24 hours.
Those allowed to enter France will need to provide evidence of a negative coronavirus test taken less than 24 hours in advance, and must isolate for at least two days.
Hauliers and transport workers are exempt from the new rules.
Travel firms described the tourism ban as a “hammer blow”.
Eurostar’s Twitter account has been inundated with messages from people wanting refunds.
The company is offering customers the opportunity to rebook without a fee, or a voucher.
Trade association Abta has requested an “urgent meeting” with Chancellor Rishi Sunak and Transport Secretary Grant Shapps to discuss the sector’s “current financial situation and its pressing need for financial support”.
Chief executive Mark Tanzer said: “The Government has recognised the plight of the UK hospitality sector, with trade down by 40% in December.
“But at the same time, the travel industry, where income has been down by 78% this year, and further impacted by Omicron restrictions since late November, continues to be ignored.
“Over the past fortnight, we have heard nothing from Government about how travel and tourism might be supported. The time to act is now.”