As of 4 AM UTC today, persons entering the UK from the Czech Republic, Jamaica and Switzerland - including returning UK residents who have visited those countries - are no longer exempt from quarantining upon arrival .
Those countries thus join Brits' #1 and #2 holiday destinations Spain and France as countries to which a trip subjects tourists to the inconvenience of a 14-day quarantine upon return.
Although the governments of Spain and France have complained about being removed from the exempt list - both are highly dependent on Brits for tourism - a majority of residents of Spain (61%) and France (55%) said in a recent YouGov poll that they want visitors from the UK banned from their countries.
The current list of UK "safe" countries is here.