The country will now be moved to the amber travel list on Tuesday following the UK Government's latest review of international travel.
The UK Transport Secretary Grant Shapps announced the decision today, which comes with a host of holidaymakers already having travelled or booked flights to the country.
He said: “I want to be straight with people, it’s actually a difficult decision to make, but in the end we’ve seen two things really which caused concern.
“One is the positivity rate has nearly doubled since the last review in Portugal and the other is there’s a sort of Nepal mutation of the so-called Indian variant which has been detected and we just don’t know the potential for that to be vaccine-defeating mutation and simply don’t want to take the risk as we come up to June 21 and the review of the fourth stage of the unlock.”
It was placed on the green list at the first review on May 7, and has since seen a significant number of UK tourists since international leisure travel became legal on May 17.
Yesterday saw Portugal confirm a further 724 coronavirus cases and one death, compared to 4,420 cases in the UK.
However, Portugal has a much smaller population, with around 10.17 million people compared to 66.8 million in the UK.
Mr Shapps defended the decision, saying only “decisive action” will help “make sure that we can do a domestic unlock”.
He explained: “I think we have to be perfectly honest and say of course things are much less certain than they would have been a couple of years ago.
“On the other hand and much more positively, we have done wonders with our vaccination programme and the rest of the world will catch up.”
No new countries were added to the green list.
Arrivals from amber destinations are required to self-isolate for 10 days upon entering the country and then take two post-arrival PCR tests.
Scottish Transport Secretary Michael Matheson also defended the move, which was made following a meeting between the UK and devolved governments as well as advice from the joint biosecurity centre.
He said: “Portugal is a popular destination for Scottish holiday makers and this change will clearly cause disruption to people’s travel plans.
“However we have been forthright from the outset that the traffic light system is designed to protect the safety of the people of Scotland and the continued progress we are making as we come out of lockdown.
“Using the stringent methodology of the Joint Biosecurity Centre it is clear the risk this new variant poses is now too great to allow unrestricted travel to Portugal, an approach that has been agreed by all four nations.
“International travel for holidaying purposes remains risky and subject to sudden change. We have said before people should think very carefully about travelling – and this latest development serves to underpin that advice – especially so given the prevalence and unpredictable nature of variants of concern.”
Nick Thomas-Symonds MP, Labour’s Shadow Home Secretary accused the UK Government of confusing the public.
He said: “The U.K. Government have caused chaos with the mishandling of travel restrictions at the border.
“The confusion over the ‘Amber List’ has led to reports of over 50,000 people travelling to the UK daily, with only a tiny percentage going into hotel quarantine and a stream of flights entering the UK from ‘Amber List’ countries. .
"Ministers also now need a clear plan to manage the confusion that will result in Portugal being removed from the ‘Green List’ so quickly and must publish all of the data behind this decision.”
Jacqueline Dobson, the President of Barrhead Travel, claimed the announcement “compounds the damage” already inflicted on the travel industry.She said: “It’s disappointing for the industry and it will be a hammer blow to the thousands of travellers who haven’t seen family or loved ones for months on end and those holidaymakers who are already abroad.
“At the drop of a hat the government has determined that these changes are required without meaningful consultation with the industry and without due consideration for the consequences.
"We have long been at the stage where a genuine, tangible route map out of this crisis is required. Sadly, it appears that this is not forthcoming and instead we hurtle from one disastrous announcement to another.
“We know that public health has to come first but the travel industry needs to see a clear roadmap to recovery or risk further permanent damage.
" Across the world, international travel is beginning to safely restart and, without imminent timelines in place for the UK, we risk falling well behind our global counterparts.”
Paul Charles, chief executive of travel consultancy The PC Agency labelled it a “terrible decision”.
He said: “They are basically putting at risk tens of thousands of jobs across aviation and the travel sector, and not showing any signs of helping the sector to recover.
“There are several countries which meet the criteria to be on the green list so this is clearly a politically charged decision rather than one based on data.”
Robert Boyle, former director of strategy at British Airways’ parent company IAG also questioned the decision.
He said: “In theory, we know what is being measured and the data sources being used, as the Government has published that.
“What we don’t know is what the thresholds are and how they get from the data to the decisions.
“I think the truth is they follow the opinion polls.”