England on Monday added seven Greek islands to its coronavirus quarantine list, but the mainland remains exempt, as the government seeks a more targeted way to limit new cases from abroad.

Transport Secretary Grant Shapps said anyone arriving from Lesbos, Tinos, Serifos, Mykonos, Crete, Santorini or Zakynthos from 0300 GMT on Wednesday must self-isolate for a fortnight.

At the same time, Britain's foreign ministry warned against all but essential travel to the seven islands, many of them popular destinations for British tourists, particularly young people.

The U.K. began introducing quarantine in June as one way to stop new infections of coronavirus, which has killed more than 41,500 people – the worst death toll from the pandemic in Europe.

But changes made with little notice and confusion over different policies in different U.K. nations – notably England and Scotland – sparked anger in the travel industry and frustration among tourists.

Shapps said quarantine measures could not be targeted at specific regions within countries as there was too much movement between high- and low-risk areas, but islands had natural boundaries.

"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," he said.

Scotland has introduced quarantine measures for arrivals from the whole of Greece, while Wales also has restrictions on six islands.