Video report by ITV News Meridian's Mary Stanley
Holidaymakers are facing a frantic race to get home from Portugal after the country was moved from the Government's green list to amber.
It means from Tuesday 8 June, anyone travelling back from Portugal will have to quarantine for ten days and take two PCR tests.
The announcement has also left thousands of people devastated now facing the prospect of having to cancel their holidays altogether.
There's also been more reaction from airlines and travel agents who say it's another massive blow to the industry.
George Brown from Yateley in Hampshire went into his travel agents on Thursday to pick up his tickets to Portugal, at exactly the same time the country was removed from the green list.
It is the fifth holiday he's been forced to cancel in the last year.
"She showed me the boarding card, and then two minutes later it was cancelled. It's just sheer disappointment.
"We were due to go to Australia in April and that was cancelled, due to go to Croatia...Russia..they've all been cancelled."
The Government says it has chosen to take a cautious approach with cases rising in Portugal.
Heathrow boss John Holland-Kaye said the travel industry is facing "another lost summer".
He said: “If the government is serious about protecting UK jobs and supporting businesses across the country, rapid action is needed to reopen flights to key trading partners, remove testing for vaccinated passengers from ‘green’ countries, and slash the cost and complexity of testing, as other G7 countries are doing.”
Watch: Holidaymakers from Portsmouth say they have had to cut their five-day holiday to three nights and change their return flights due to the latest travel changes
Extra flights are being laid on on Friday night (4 June) to get passengers back to airports.
Those with holidays booked to Portugal face the prospect of of trying to get a refund or re-book their holiday, in the hope the situation might change.
What are the rules for people returning from each category?
Green: There is no need to self-isolate. Take a pre-departure test and a PCR test on day two of your arrival in the UK.
Amber: Self-isolate for 10 days, unless you receive a negative result from a test taken at least five days after arrival. Take a pre-departure test, and PCR tests on day two and day eight of your arrival in the UK.
Red: Spend 10 days in a quarantine hotel. Take a pre-departure test, and PCR tests on day two and day eight of your arrival in the UK.