The government's own scientific advisers have cast doubt on the effectiveness of a plan for partial travel bans to stop new coronavirus variants being imported.
They said that a "reactive, geographically-targeted" approach "cannot be relied upon", after the government moved to block all non-UK nationals and residents arriving from parts of southern Africa and South America.
The advice came on 21 January at a meeting of the Scientific Advisory Group for Emergencies (SAGE), as the experts said there wold be a "lag between the emergence and identification of variants of concern".
And they cautioned someone coming from a country where travel is banned could still bring a coronavirus variant across the border by "indirect travel via a third country".
The evidence comes despite ministers reassuring the public they are following the science, and rolling out a hotel quarantine policy SAGE also did not fully endorse.
Minutes released on Friday from the meeting more than two weeks ago said: "No intervention, other than a complete, pre-emptive closure of borders, or the mandatory quarantine of all visitors upon arrival in designated facilities, irrespective of testing history, can get close to fully prevent the importation of cases or new variants."
Six days later, prime minister Boris Johnson announced a plan to force UK nationals and residents arriving in England from around 30 countries to isolate in government-provided accommodation, beginning on 15 February.
Labour have called for the scheme to be expanded to cover all people arriving in the country, as Scottish first minister Nicola Sturgeon has announced will apply north of the border.
Sir Keir Starmer asked Mr Johnson in parliament on Wednesday this week: "Why did the prime minister choose not to do the one thing that SAGE said could prevent new variants coming to the UK?"
But Mr Johnson said SAGE had not recommended "a complete ban" and in fact said "a travel ban should not be relied upon to stop the importation of new variants".
He added: "It is not practical completely to close off this country."
Currently, non-UK nationals and residents are banned from travelling into England from Portugal, southern African countries including Namibia, Zimbabwe and Botswana, as well as the South American nations like Argentina, Brazil and Columbia.
Fears have been raised over the spread of the South African COVID-19 variant, after at least 11 cases of community transmission in eight different postcodes were discovered.
The variant is not believed to have a significantly greater effect on hospitalisations or deaths. Coronavirus vaccines are still effective against it, but may be less so.
