Vacationers returning to Britain from Portugal or its island territories of Madeira and the Azores will now not have the ability to keep away from quarantining as of Tuesday, British officers introduced on Thursday, complicating the plans of Britons hoping for straightforward getaways to the nation this summer season.

In mid-Could, Britain had put Portugal and 12 different international locations and territories with low coronavirus caseloads on a “inexperienced checklist,” permitting British guests to keep away from a quarantine interval on their return dwelling from these places.

As instances stay usually low in Britain, residents fatigued by a depressing winter and a four-month nationwide lockdown began flocking to Portugal, as a result of many of the different green-listed locations have been both not accepting vacationers or weren’t already favored locations for British vacationers. The method nonetheless concerned a number of types and P.C.R. virus exams, whose prices might complete lots of of {dollars}.

The choice to maneuver the nation off the inexperienced checklist was a “safety-first strategy,” Grant Shapps, Britain’s transport secretary, told the BBC on Thursday.

Portugal had remained on Britain’s inexperienced checklist at the same time as the speed of optimistic coronavirus instances there rose 37 % over the previous two weeks, and British followers poured into the town of Porto to see two of England’s high soccer groups, Chelsea and Manchester United, face off within the Champions League last final Saturday. (Chelsea won.)

Portugal has seen the unfold of the virus variant first recognized in India, now known as Delta, Mr. Shapps mentioned in a public statement launched on Thursday.

Officers didn’t add any new international locations to the inexperienced checklist, dealing a blow to Spain, which had hoped to be added after seeing its virus numbers enhance. Britain was the most important supply of abroad vacationers to Spain earlier than the pandemic, accounting for 18 million of just about 84 million international guests in 2019.

The announcement disillusioned British guests who had already booked journeys to Portugal, or hoped for wider journey in Europe. It additionally dismayed a journey business that has suffered within the pandemic.

The choice to not add international locations to the inexperienced checklist “is a complete catastrophe for the already fragile journey business and is more likely to result in additional airline failures and plenty of extra job losses,” Brian Strutton, performing normal secretary of the British Airline Pilots Affiliation, mentioned in a statement. “Our airways want this summer season season if they’re to outlive.”

In Portugal, distributors had been excited to welcome again vacationers, usually a significant monetary enhance for the nation. However some folks had grumbled about international guests not following native restrictions, together with outside mask-wearing and a ten:30 p.m. curfew.