Only fully-vaccinated Brits can now visit mainland Portugal without undergoing a 14-day quarantine. Visitors from the UK could previously avoid the mandatory 14-day isolation if they had evidence of a recent negative test for the CCP (Chinese Communist Party) virus. The new rules come into effect today to try to stem any influx of the so-called Delta variant from the UK, where cases have risen rapidly, according to official figures. The variant now accounts for more than half of all infections in the country. Tougher rules are also being announced for the Balearic Islands, another popular holiday destination for Brits. The tough stance taken by Portugal puts UK holidaymakers in the same risk category as those from South Africa, Brazil, India, and Nepal. Travellers from Portugal to the UK must quarantine for 10 days on arrival, after the government took the country off the green list.  Children under 12 will …