Thousands of British holidaymakers are facing two weeks in quarantine as new restrictions for those returning from France and the Netherlands come into force.
Travellers arriving from France, the Netherlands, Monaco, Malta, Turks & Caicos & Aruba must self-isolate for 14 days if they arrive in the UK after 4am on Saturday.
Transport Secretary Grant Shapps, who announced the decision on Thursday night, insisted the Government had taken “a practical approach” to the new restrictions.
But the move drew backlash on Friday as 160,000 Brits holidaying in France faced a race against time to book flights, ferries and Eurostar trains back to the UK.
Travellers faced a struggle getting back to the UK on Friday as many direct fights were sold out.
One-way air fare costs for Paris to London flights soared above £450, with the lowest priced Eurostar tickets available on Friday morning priced at £210.
A Eurostar spokesman said 12,000 people tried to book tickets in the hour after the new rules were announced at around 10pm on Thursday, compared with just hundreds normally.
A traveller who gave her name as Sonata K, a 39-year-old dentist, was due to head to Paris on Eurostar for four nights with her mother but cancelled her plans after finding out about the quarantine measures at St Pancras on Friday morning.
"It’s not worth it to go out and have to self isolate," she said.
“With my work I can’t do the procedures from home.
“We were too late to get the news, we’re just finding out here but it’s better than on the train.”
Holidaymakers Stuart and Anna Buntine spent nearly £1,000 to make it home via Eurostar from Burgundy, central France.
Mr Buntine, 58, said: "I went to bed last night thinking it was all OK, woke up at 7am to find we had to get back here pretty sharpish.
"We couldn’t get tickets, all the sites had crashed… we had to buy business class tickets back today so it’s cost nearly £1,000."
Mrs Buntine added: “We left here with our eyes (open) knowing that it was a possibility, so we decided we’d take that risk."
Stephanie Thiagharajah, who is French but lives in Kent, said she had a “really stressful evening” on Thursday booking a train to London from Paris with her young son after getting a quarantine notification at around 10pm.
She said outside St Pancras: “It was awful. It’s really a manic way of managing it, creating a huge amount of people coming at the same time. It’s probably more risky than staggering it.
“It was our first time seeing family since Christmas and we were meant to be coming back on Sunday, I had to pay £250 to change.
“Within minutes after 10pm last night the train booking service had more than 3,000 people queueing and the website crashed.
“The Eurostar was full of families, scared to be quarantined, they were definitely annoyed.”
Dyan Crowther, chief executive of the HS1 high-speed London to Channel Tunnel rail link, said it was "heartbreaking" seeing families having to cancel holiday plans and spend hundreds of pounds dashing home to beat quarantine.
"People want certainty, they want to know that they can go away without having to worry about what the world will look like when they return," she said.
"My heart goes out to them."
A spokeswoman for travel trade organisation Abta said the Government’s quarantine policy will "result in livelihoods being lost unless it can step in with tailored support for the travel industry".
Consumer expert Rory Boland of Which? magazine attacked the "cynical behaviour" of some airlines as holidaymakers try to return from France before quarantine rules are imposed, and urged reform of the travel industry.
He said: "We’ve seen some airlines hiking prices for people scrambling to get home from France, while also refusing to refund or offer flexibility to those in the UK who can no longer take their holiday by claiming schedules are operating as normal - despite Government advice against all but essential travel.
"The cynical behaviour of certain carriers has a knock-on effect for package operators, who are struggling to refund passengers when they can not claw back their money from the airlines.
"The impact on trust in the travel industry has been devastating."
The Joint Biosecurity Centre and Public Health England detected a significant change in Covid-19 risk in all six destinations for which quarantine restrictions are being imposed.
Spain and Malta are among six European countries currently recording a seven-day rate of over 50 new cases of Covid-19 per 100,000 people.
Department for Transport officials said data from France shows that over the past week there has been a 66 per cent increase in newly reported Covid-19 cases and a 52 per cent increase in the weekly incidence rate per 100,000 population, indicating a sharp rise in infections.
Mr Shapps told BBC Breakfast there "had to be a cut-off".
He said: “It’s a practical approach as well, which has enabled all fours parts of the United Kingdom, Scotland, Wales, Northern Ireland and England, to implement the same time at 4am where there are no flights in the air, at least tomorrow."
Prime Minister Boris Johnson echoed the Transport Secretary's comments, saying: "We have got to be absolutely ruthless about this, even with our closest and dearest friends and partners. I think everybody understands that."