Holland and Malta could become the next countries to be removed from the UK government's safe list after a rise in coronavirus cases.
The increase in infections mean holidaymakers could be forced to quarantine upon return from the two countries.
Officials are keeping a close eye on the number of cases, infection rate and testing figures in a number of countries.
On August 6, the government announced that Belgium, The Bahamas and Andorra were being added to the quarantine list two days later.
It follows fears that France could next be removed from the list - with 29.4 cases per 100,000 people.
Meanwhile, the Netherlands has spiked to 34.6 while Malta has soared to 63.
On August 10, Prime Minister Boris Johnson warned that the government wouldn't "hesitate" to impose further restrictions on countries if needed.
On a visit to Upminster, in east London, he added: "I don't want to advise people about their individual holidays, individual decisions, they should look at the travel advice from the Foreign Office clearly.
"But what I will say, and I hope people would expect us to do this, in the context of a global pandemic, we've got to keep looking at the data in all the countries to which British people want to travel.
"Where it is necessary to impose restrictions or to impose a quarantine system, we will not hesitate to do so."
Spain - which was previously removed from the list when the rate hit 39 - currently stands at 90.3, according to the latest figures from the European Centre for Disease Prevention and Control.
By comparison, in the UK, there are 17.1 cases per 100,000 people.
The PM's official spokesman told The Sun: "We can amend the list at any time.
"We can remove countries, but if there's a sustained improvement in the health situation in a particular country we can reinstate exemptions."
