Portugal now stipulates adults need only present a valid vaccination certificate on arrival and that children under 12 do not need to present a test.

Adults and children over 12 who are not fully vaccinated can take a supervised lateral flow test 24 hours before boarding. 

The requirement for a passenger locator form remains for all arrivals.

Visit Portugal said the PLF had to be completed “after check-in and before departure”, adding: “The QR code generated when filling out the PLF can be presented in paper or digital format, without which boarding will be denied.”

The rules are slightly different in the Azores, where international arrivals must present an antigen test taken 48 hours before departure. Children 12 and under can travel without a certificate or test. UK arrivals must fill in an online questionnaire that is different from one demanded by the mainland.

Madeira also has its own rules and currently levies no restrictions on entry apart from the need to register at madeirasafe.com.

Greece has also dropped the requirement to take any pre-departure test provided travellers can demonstrate full vaccination status.

However, it has a lower age threshold, meaning more children who are not double jabbed or vaccinated at all will fall foul of the age limit. This may affect family bookings as many children will need to take an antigen test 24 hours before arrival.

The UK FCDO said: “The measures to enter Greece apply to all travellers aged five and above. Children under five do not need to provide a negative test for entry to Greece.”

The relaxations will put pressure on Spain, whose entry rules for children are inhibiting UK travel to the country.