As Portugal reopened to UK visitors this weekend, it makes it one of the most guaranteed holidays during these tough times. As of course, it is not guaranteed, it is very unlikely for the UK government to remove Portugal from the travel corridors list on September unless in case of a large virus outbreak there.
Currently, there are last few flights from London Luton or Stansted to Faro Algarve Airport with Ryanair left so take them before its too late as they are to be sold out quickly.