Greece, Switzerland and the Czech Republic risk being subject to quarantine measures by all four nations of the UK, according to latest figures.
A seven-day rate of 20 Covid-19 cases per 100,000 people is the threshold above which the UK Government considers triggering quarantine conditions.
Switzerland is currently recording a seven-day rate of 20.7 cases per 100,000, the latest data shows. Scotland has already taken Switzerland off its list of countries from which people do not need to self-isolate on arrival - but the rest of the UK could follow later this week.
The Czech Republic and Greece are also likely to have their Covid-19 figures scrutinised closely by the UK Government this week.