The UK government has begun to introduce a more nuanced approach to quarantine restrictions, separating some islands from mainland countries.
As a result, seven Greek islands have been removed from the current safe list.
Visitors arriving back in England from Crete, Lesvos, Mykonos, Santorini, Serifos, Tinos and Zakynthos will be expected to isolate for 14-days from 04:00 on Wednesday morning.
At the same time, the Foreign, Commonwealth & Development Office (FCDO) has updated its travel advice for Greece to advise against all but essential travel to the islands.
The rest of Greece remains exempt from advice against all non-essential international travel.
Transport secretary, Grant Shapps, explained: “Our top priority has always been to keep domestic infection rates down, and we are taking the next step in our approach.
“Through the use of enhanced data we will now be able to pinpoint risk in some of the most popular islands, providing increased flexibility to add or remove them – distinct from the mainland - as infection rates change.”
Announcements on which islands and countries will be added or removed will continue to be made as part of the current weekly process, Shapps added.
Despite wide-spread calls from the travel industry to be more selective in quarantine restrictions, the transport secretary said this was not currently possible.
“It is not considered safe to implement a fully regional system for international travel corridors - there is too much movement between high risk and lower risk regions within single countries and regional health information is not sufficiently reliable.
“However, when a region has natural boundaries – like an island – the risks reduce,” Shapps added.
Any changes will, therefore, only apply to land that has a clear boundary or border where there is robust, reliable and internationally comparable data available.
The island must also have direct flights to the UK or at a minimum, transport must have taken place through exempt territories.