France has become the latest country where returning Brits will need to quarantine - and the UK's transport secretary has now revealed how the government could choose which destination might have its air bridge scrapped next.
Grant Shapps told LBC this morning that any country recording above 20 cases of Covid-19 per 100,000 people in a week causes "concern" and can "trigger" introduction of quarantine measures, requiring inbound travelers to self isolate for two weeks.
This means Denmark, the Czech Republic, Switzerland and Croatia could all be next in line, Telegraph analysis of the latest coronavirus figures shows, with infection rates above 14 per 100,000 and rising.
And there could be fears for Greece and Ireland, where new cases are rising at speed.
The rate of infection over the last seven days in the UK itself is hovering at around half the government's threshold with 9.7 cases per 100,000.
Behind France and the Netherlands, which are due to be removed from the list of air bridges this weekend, 11 countries currently exempt from quarantine restrictions have seen weekly infection rates higher than 10 per 100,000 people.
Three of those - Australia, Iceland and Cyprus - have seen the week-on-week change in the infection rate fall, indicating they are more likely to be safe from having fresh travel restrictions imposed.
But Denmark, the Czech Republic and Switzerland, where the infection rate is now above 14 per 100,000, are all seeing the number of cases rise, putting them at risk of triggering a 14 day quarantine for travellers on return.
Croatia's rate stands just below 14 per 100,000, but has nonetheless seen a week-on-week increase.
In Denmark, where the rate is currently 15.3 per 100,000 in the week to August 13, cases have risen by 61 per cent week-on-week.
The rate of infection is broadly similar in the Czech Republic and Switzerland, at 14.4 and 14.3 respectively.cases are rising by 7.5 per cent and 10 per cent week-on-week, suggesting if the trend continues both countries will approach the quarantine benchmark more slowly.
The same cannot be said for countries including Greece and Ireland, where the infection rate is rising at speed.
In Greece, which saw an infection rate of 11.6 per 100,000 in the week to August 13, the week-on-week change is up to 90 per cent, as weekly cases rose from 259 to 637.
Ireland's infection rate is lower at 10.8 - in similar territory to Australia. But the week-on-week change has been 47.9 per cent - higher than in France.
The transport secretary said on Friday once infection rates reach 10 per 100,000 people it can "trigger" the removal of travel corridors, meaning travellers will have to self-isolate when they arrive in the UK for 14 days.
He told the Today programme: "With France and these other countries, Netherlands and elsewhere, the numbers have now just gone above the threshold, which is about 20 case per 100,000, but measured on a seven day rolling average.
"That is what the Joint BioSecurity Centre will be looking at," he said, noting France had "breached" the level.
Among many smaller countries, the infection rate is now well beyond this level, likely given greater flexibility due to lower case numbers.
In Aruba and Turks and Caicos, removed from the air bridges list alongside France and the Netherlands, the weekly infection rate was 587 and 289 per 100,000 respectively.
But with population of just over 100,000 in Aruba, and below 40,000 in Turks and Caicos, it required very few cases to cause infection rates to soar.
Aruba saw 627 cases in the week to August 13, and 112 in Turks and Caicos.
A handful of other smaller countries remain on the Foreign and Commonwealth Office list of those exempt from quarantine, but have infection rates significantly higher than 20 per 100,000.
The Faroe Islands saw a rate of 200 per 100,000 in the week to August 13. But with a population of fewer than 50,000, it equates to just 98 new cases.
A similar picture is emerging in Gibraltar and Monaco, where infection rates are now above 40 per 100,000.
With populations of fewer than 40,000, they saw new cases in the week to August 13 of just 14 in Gibaraltar and 16 in Monaco.
It remains to be seen whether countries will be introduced to the list of air bridges, with infection rates in Portugal now down to 13.5 per 100,000.