Holidaymakers could be allowed to travel to international locations as soon as May 17 under the Government’s plans for the easing of lockdown. However, based on the traffic light system that indicates which countries are safer to travel to, Britons can currently only chose from eight countries if they wish to enjoy quarantine-free holidays.

New modeling conducted by Robert Boyle, former strategy chief at BA and its owner IAG, listed USA, Gibraltar, Israel, Iceland, Ireland, Malta, and Australia and New Zealand as green list nations.

The Government is set to review the system on June 28 and popular tourist destinations such as Spain and Greece – which currently remain on the amber list – could turn green if their coronavirus figures improve.

The study read: “Last year, the Spanish and Greek islands were given a lower-risk rating than the mainland and that could happen again this year.”

The report labeled Gibraltar as “the surest case for green,” adding that “ it has essentially zero cases of any type and the population is fully vaccinated.”

It added: “Israel must be the next most likely. Again, it has vaccinated close to its entire population and case numbers are below even last year’s threshold.”

There is currently speculation over whether India should be added to the red list after a new coronavirus variant was first identified there.

The UK has already detected 160 cases of the variant, which has a “double mutation” in the spike protein, E484Q and L452R.

The strain is currently dubbed a “variant under investigation” rather than a “variant of concern” by the UK health authorities.

Professor Beate Kampmann, director of the Vaccine Centre at the London School of Hygiene and Tropical Medicine, stressed that herd immunity may not work in a scenario where various strains of coronavirus are in circulation.