Vaccinated Britons would avoid Covid tests and quarantine under government plans to allow foreign summer holidays.
Boris Johnson is expected to signal on Monday that, when foreign travel is opened up, restrictions will be based on a traffic light system under which countries are rated red, amber or green according to their risk based on vaccination levels, Covid rates and prevalence of variants.
All travellers returning to the UK will be expected to have pre-departure Covid tests irrespective of their vaccination status under proposals drawn up by the Government's global travel taskforce.
However, The Telegraph understands that those who have been fully vaccinated with two jabs could need fewer tests after visiting low-risk countries. They may not have to quarantine for 10 days on return from medium-risk countries including popular Mediterranean destinations.
"For amber countries, you would remove home quarantine. The debate is whether there will be any testing required instead of quarantine," said a government source.
Details of how a vaccination certificate for travel could work are unlikely to be announced until the taskforce publishes its report on April 12. However, Mr Johnson hinted at the role of vaccinations on Thursday when he said: "There's definitely going to be a world in which international travel will use vaccine passports."
So far, 4,948,635 people in the UK have been fully vaccinated, with a record 435,177 second doses having been given on April 1. To date, 31,301,267 first doses have been given.
Ministers are understood to be aiming to end the current ban on non-essential travel on May 17 and replace it with the traffic light system, but final decisions will depend on a further review of the risks as Europe battles a third Covid wave and struggles with low vaccination rates.
The number of countries on the "green list" for quarantine-free travel could initially be limited to as few as 12, with just a handful in Europe – as revealed by The Telegraph earlier this week – and a wider opening of travel delayed until July or even August.
The plans, being considered by the Government's global travel taskforce, could see fully vaccinated holidaymakers returning from "green list" countries enter the UK without any tests on arrival provided that they have negative results from a pre-departure test.
In contrast, unvaccinated holidaymakers would need a further test on their return – most likely to be a cheaper rapid lateral flow test. Fully vaccinated travellers from "amber list" countries, including popular European destinations, may only need one further test on arrival before sidestepping the 10-day quarantine at home.
Unvaccinated holidaymakers, however, would still have to self-isolate at home for 10 days and have tests on days two and eight. Officials are considering whether they could be released earlier from quarantine if they test negative.
"Red list" countries rated as high risk because of Covid variants will still be subject to a travel ban, with any Britons returning from them required to quarantine in hotels at a cost of up to £1,750 per person with tests on days two and eight.
Government sources said no final decisions had been taken and discussions were "fluid", meaning the plans could change. "We're not ruling anything out, but it's all still under review and nothing [is] decided yet," said a senior source.
Countries such as Greece, Cyprus and Croatia are already pledging to offer vaccinated Britons quarantine and test-free entry to their countries for the summer. The Foreign Office is leading talks with other governments to secure bilateral agreements for vaccinated travellers and testing regimes for other holidaymakers.
On Friday night, the US announced that vaccinated Americans would be free to travel abroad without the need for tests and could return without having to undergo quarantine in a mirror image of the scheme being considered by the UK.
It follows research by the US Centers for Disease Control and Prevention which suggested that vaccinated people did not "carry the virus" and were unlikely to spread it to other people.
However, while urging families to follow the lockdown rules over the Easter weekend on Friday, Mr Johnson said Covid vaccines did not give "100 per cent protection" or "entirely reduce or remove the risk of transmission".
A senior source said ministers intended to maintain border checks of all arrivals' passenger locator forms to prevent abuses of the new traffic light system.
However, the move is likely to fuel criticism of a two-tier society that potentially discriminates against those who are not vaccinated. More than 70 Tory, Labour and Liberal Democrat MPs have criticised Mr Johnson over his plans for domestic vaccine certificates amid warnings that they risk creating a "checkpoint Britain".
Prof Robert West, a psychologist at University College London and member of the Scientific Advisory Group for Emergencies, said the "balance of evidence is against" the widespread adoption of vaccine certificates. He said they could be discriminatory and give a false sense of security.
However, the moves on vaccinations will be welcomed by the travel industry. Paul Charles, the chief executive of consultancy The PC Agency, said: "Other governments have been telling Westminster that they will welcome fully jabbed British travellers with open arms.
"This is also a clever way for the Government to boost vaccine uptake, especially among younger people, which has been a hurdle in Israel. If you want to travel seamlessly, then get the full jab as soon as you're offered it."