A hotel quarantine system targeted at arrivals from high-risk countries will be announced by the home secretary, Priti Patel, on Wednesday, after ministers met to sign off the more targeted approach. Boris Johnson rejected calls at Tuesday evening’s meeting for a blanket policy, opting instead for imposing hotel quarantine on British citizens from a limited number of countries such as South Africa and Brazil. Ministers were presented with a number of options, with some – including Patel and the health secretary, Matt Hancock, in favour of a more blanket approach, a larger number of countries on the list, or even a temporary closure of UK borders. Labour said a country-by-country quarantine policy would be “half-baked” and leave the UK’s vaccination programme vulnerable to as-yet-unknown strains of coronavirus. Patel will give a statement to the House of Commons on Wednesday setting out the measures after prime minister’s questions. The policy is expected to take a number of weeks to implement. The UK will reserve the right to expand measures beyond what was agreed on Tuesday evening, a government source said. Bans are already in place on visitors from South Africa, Portugal, Brazil and other South American countries in a bid to control the spread of new variants of Covid-19. Labour said on Tuesday that it was calling for a comprehensive hotel quarantine system. The shadow home secretary, Nick Thomas-Symonds, told the Commons the policy “cannot be restricted to only a handful of countries, leaving gaping holes in our defences against different strains of the virus emerging around the world, and the government must announce a sector support package for aviation”. He described the limited policy as “half baked” saying: “From the start of the pandemic the government’s handling of measures with the border has been chaotic.” Patel told MPs that the UK had “a world-leading vaccination programme … We are proud of that programme and the government will do everything that it can to protect that vaccine from new strains of the virus.” She is understood to have argued privately that a more comprehensive quarantine scheme would protect the UK from as-yet unknown new variants. Scientists said they favoured the blanket approach, highlighting that most countries do not have sophisticated surveillance systems that can detect existing or new variants, which makes limiting the policy to certain countries futile. “The big thing about infectious diseases is that they don’t respect international borders,” said Paul Hunter, a professor in medicine at the University of East Anglia. But Hunter questioned whether the policy was sustainable over the longer term. “I think there are some benefits to this, but we can’t rely on it, and the crucial thing is to make sure we vaccinate as many of our population as we can.” Susan Michie – a member of the Scientific Pandemic Influenza Group on Behavioural Science, a Sage subcommittee – added that limiting the policy to only certain countries may incentivise people to travel from one country to another before entering Britain. Within the UK, data suggests a quarter of people who are supposed to be self-isolating still think they can go to the shops, Michie said. “I don’t think British people are necessarily different than people from the rest of the world. People are likely to go out unless it’s really managed and well supervised.” Gabriel Scally, a visiting professor of public health at the University of Bristol and a member of the Independent Sage committee, said there was no evidence that the voluntary self-isolation policy had been satisfactory. Regarding the targeted approach to certain countries, he said: “At the best, it’s a very poor sticking plaster and it will … certainly not stop the entry of new variants to the UK.”