A meeting on Downing Street later in the day will finalize any changes to the categorization of countries in the "traffic light" system adopted by the British government since it reintroduced leisure travel.
Boris Johnson has come under a lot of pressure from both lawmakers and the travel industry to expand the green list, which currently includes just 12 states and territories.
Arrivals to the UK from these countries are only required for two diagnostic tests, while those traveling from the orange list countries to which most European destinations belong are required to undergo three tests and a ten-day isolation at home.
Asked, however, about the forthcoming first revision of the categorization of British travel destinations, Mr Johnson said he had to wait for the recommendations of the Single Biosafety Center, which assesses epidemiological data by country.
Although the British Prime Minister said that the government will try to allow citizens to travel, he noted that he should be careful. He stressed that he would not hesitate to put "green" countries in the orange category, a comment that was taken as a possible reference to Portugal, the only popular European destination that is so far on the green list.
"I want you to know that we will not hesitate to move countries from the green list to the orange list and from there to the red list, if we have to do it," Johnson said. The red list currently includes 43 countries, including Turkey. Arrivals from there are only allowed for British nationals and they, in addition to the tests, must pay for a ten-day quarantine at a default hotel.
Announcements for the first review are expected this afternoon and the new lists will take effect on Monday.
According to the Telegraph, more countries are more likely to be on the red list than on the green. Malta is considered the strongest candidate for inclusion in the green list.
Travel analysts estimate that the debate on specific islands of Greece and Spain remains open, while for countries such as Cyprus, mainland Greece and other European countries, the most realistic date for inclusion in the green list is June 28, ie in the next review.
The delay is expected to give the Border Service time to better prepare after the revelation of a government report warning of four-hour queues at Heathrow over the summer due to increased arrivals and health check checks.
There are also concerns that the diagnostic test analysis system could not currently handle the increased volume of examinations if the green list was greatly expanded.
Source: KYPE