A traffic light system is being considered by ministers for when international travel restarts, which could rate countries green, amber and red depending on the state of vaccine passport agreements. The Guardian has been told the scheme could come into operation from August, with hotel quarantining continuing until at least 21 June for UK nationals and residents returning to England from countries with high prevalence of coronavirus variants of concern. Work is under way across Whitehall to come up with a plan for letting people in England go abroad again, given lockdown is loosening at home while cases and deaths decrease and vaccinations are carried out at a fast pace. The government is nervous about letting people go abroad again because of concerns about the Covid variants first found in Brazil and South Africa that are believed to be more infectious and other countries lagging behind in vaccinations. But there is pressure from the UK aviation, tourism and hospitality industries for the country to open up as summer approaches. A Whitehall source said ministers discussed the idea of a traffic light system at a meeting of the government’s Covid operations committee – known as Covid-O – in early March. They signalled that the current plan is for green to indicate countries that UK residents and nationals will be able to visit without needing to quarantine on arrival, while red will be countries where enforced self-isolation will still apply, and amber will be where mixed policies apply. Multiple government sources did not deny the plan was being discussed, but stressed no decisions had been taken yet. Vaccine passports were dismissed for months by cabinet ministers. Michael Gove, the Cabinet Office minister, was asked on 1 December if the government was considering introducing them, replying: “No, that’s not being planned. I certainly am not planning to introduce any vaccine passports and I don’t know anyone else in government [who is].” But on 11 February it was revealed their use was to be discussed by ministers at another Covid-O meeting. Soon after, Boris Johnson announced several reviews, including one to “consider the resumption of international travel”, and also the domestic use of vaccine status and test result certificates. When asked on Monday about the prospect of a traffic light system linked to vaccine passports, the prime minister’s spokesperson did not deny the suggestion, but urged people to wait for the reviews to conclude on 12 April. “The travel taskforce is looking at travel,” they said. “I can’t preempt that.” Johnson has spoken before about his discomfort with vaccine passports and certificates, but signalled they may be a necessary way to reopen sectors of society. The move would probably aggravate some libertarian Tories. Steve Baker, the deputy chair of the Covid Recovery Group of Conservative MPs, said recently that vaccine passports would “create a two-tier society”. He said they would be unnecessary, because “all who want to be vaccinated will be”, and “discriminatory”, as “it is unlawful to discriminate against age, disability, pregnancy and religion or belief”. The EU commission president, Ursula von der Leyen, backed the idea of using certificates to identify people who have had the jab earlier this year, but added: “Whether that gives a priority or access to certain goods, this is a political and legal decision that has to be discussed on the European level.” The Greek tourism minister revealed last month that his government was in “preliminary discussions” with the UK government over a potential travel agreement for Britons who have been vaccinated. Spain’s tourism minister also said his government would consider a “green corridor” for vaccinated British tourists if there was no EU agreement. And Denmark and Sweden are already working on plans for some form of digital certification for vaccination. Some travel companies have already made vaccines compulsory. Saga requires its cruise passengers to have had both doses of the vaccine at least 14 days before departure.