As coronavirus cases in Portugal go up and down, fears are growing that Britain will reimpose a quarantine for people travelling from the country.
It has been less than two weeks since Britain, Portugal's leading source of tourism, lifted a 14-day self-isolation rule for travellers arriving from Portugal.
The announcement was a relief for the tourism sector, which struggled as restrictions kept visitors away over the summer.
The number of passengers arriving from Britain has grown by a whopping 190% since Portugal was removed from Britain's quarantine list.
But a steady count of several hundred new cases per day over the last week raised fears Britain would put Portugal back on the list.
Last Thursday, health authorities reported 401 new infections, the highest since early July. Cases have since dropped, with 231 on Tuesday, bringing the total to 58,243.
British ambassador Chris Sainty said on Monday the embassy has been working closely with Portuguese authorities to understand the situation but "things can change quickly".
"As cases rise across Europe, quarantine has been reintroduced for many countries, in line with UK's overriding goal to protect public health," he tweeted.
British media reports said the number of daily cases in Portugal meant it may be forced back on to the quarantine list. A spokesman for Prime Minister Boris Johnson declined to comment.
"If the news is confirmed it would have a huge impact on the number of tourists," said Eliderico Viegas, president of Algarve's AHETA hotel association. "I'm worried."
(Reporting by Catarina Demony, Additional reporting by Victoria Waldersee, Patricia Vicente Rua and Sergio Goncalves, Editing by Giles Elgood)
