Asked by journalists during a visit to a scientific laboratory in Hertfordshire, North London, Boris said that it is "very important" to look "at everyone's opportunities" (…) in the coming months to have two vaccines.

However, he stressed that the priority will be to protect the country from the entry of new variants of coronavirus.

“This is going to be, no matter what, a difficult year to travel. There will be problems, there will be delays, because the priority must be to keep the country safe and prevent the virus from returning”, he explained.

The British press has reported, based on anonymous government sources, that the exemption from quarantine is being studied for people with two doses who arrive from countries on the “amber list”, such as Portugal.

According to the Daily Telegraph, the Ministry of Transport will propose to exempt vaccinated adults and unvaccinated children from the isolation currently required for Britons who arrive from holiday destinations such as Spain, Italy, France or Greece.

Countries on the “amber list” are subject to tighter restrictions, namely a 10-day quarantine on arrival in the UK, and two PCR tests on the second and eighth days.

With regard to the "green list", currently limited to 11 countries and territories, exempts travellers arriving in British territory from quarantine and testing, although they are still required to get a PCR test before boarding.

The “red list” requires a 10-day quarantine, plus two PCR tests, and travel is prohibited for non-essential reasons for those countries.

Scotland, Wales and Northern Ireland set their own rules but have the same 'traffic light' system for international travel and have followed England.

The review of the composition of the "green list", made every three weeks, takes place this Thursday, but several ministers have ruled out the possibility of being extended in the short term and the British press suggests that the new rules may only come into force in the end of July.

Due to the rapid spread of the Delta variant, the British Government last week decided to postpone to 19 July the fourth stage of the easing of lockdown plan which foresees to eliminate most of the restrictions, namely in terms of big events and the capacity of closed spaces.

The British Government hopes that by that date all adults will have received at least one of the doses.