Health officials are hunting for a person in the UK who is infected with a worrying Brazil variant of Covid-19 in a bid to stop it spreading into the wider community.

Dr Susan Hopkins, strategic response director at Public Health England (PHE), said the person was thought to have been tested on February 12 or 13, possibly via a home postal test or a test collected from a local authority.

She said the individual may not have completed their form completely online, or may have thought they did, and may not have got their results.

“We are looking at where the test may have been sent from and to, working with the postal services and the courier services,” she told BBC Radio 4’s Today programme, adding that the public appeal was a “belt-and-braces approach”.

In total, PHE has identified six UK cases of the concerning P1 variant first detected in the Brazilian city of Manaus – three in England and three in Scotland.

Three cases are Scottish residents who flew to Aberdeen from Brazil via Paris and London, who all tested positive while self-isolating.

Other passengers who were on the same flight to Aberdeen are now being traced.

The other two cases in England are from the same household in South Gloucestershire after one person returned from Brazil on February 10 – just days before the Government’s hotel quarantine rule came into force.

Two other people in the same household have also tested positive but are not currently included in the UK case total of six, while tests on their type of coronavirus continue.

Officials are searching for passengers who were on the Swiss Air flight LX318 from Sao Paulo to Heathrow, via Zurich, which landed on February 10.

Surge testing will now be carried out in the Bradley Stoke, Patchway and Little Stoke areas of South Gloucestershire to capture any potential spread in cases.

Dr Hopkins said the Brazil Manaus variant is similar to the variant from South Africa, with mutations that are thought to increase transmissibility.

There are also concerns that the Manaus variant can re-infect people who have previously had Covid, and that it has the ability to lessen the impact of vaccines.

Dr Hopkins said: “Manaus in particular reported that a number of individuals were re-infected with this variant, and therefore that suggests that having had prior immunity from primary infection wasn’t enough to reduce infection and transmission. And that may also impact on the vaccine.”

However, she said that although cases have been detected in the UK, it is hoped that it would not become a dominant variant.

“I think the importance here is that, while we’re in national restrictions, while we have very transmissible variants that are circulating, then we hope that there are not any other variants that will be able to take over,” she said.

“However, as we start to release national restrictions with the schools going back on March 8, that is where the risk starts to increase, and that’s why we really are clamping down on a number of measures to prevent the spread of these variants.”

She said those people identified with the variant so far had all followed the rules – including quarantining and getting tested when symptoms emerged.

She added: “We haven’t detected it in any individual who hasn’t had a history of travel or had contact with travel yet, so that is good news. But we are prepared to search it out in the communities, if it is there.”

Labour leader Sir Keir Starmer said the discovery showed the Government had not “secured our borders in the way we should have done”.

Meanwhile, vaccines minister Nadhim Zahawi said any community transmission of the variant would be identified “very, very quickly” through both regular PCR and lateral flow testing.

“We would pick up community transmission of this variant very, very rapidly, because we are able to genome sequence so quickly,” he told the BBC.

Asked if it was known whether the unidentified person with the Manaus variant had travelled to the UK or contracted the virus here, he said: “We don’t.

“Part of the reason why we want to locate them quickly is to understand more about them and their movements.”

The minister also sought to defend the UK’s border controls, following accusations the Government has been slow to implement hotel quarantine measures.

“I would say to you that the border controls that we have are pretty stringent,” he told the Today programme.

“Even countries that had hotel quarantine, like Australia, still have to deal with the variants actually challenging them in the same way they challenge us.”

Elsewhere, Graham Medley, professor of infectious disease modelling at the London School of Hygiene and Tropical Medicine and a current member of the Scientific Advisory Group for Emergencies (Sage), said it was “inevitable” that new variants would come into the country via travel.

He said: “It’s inevitable, the risk is never zero – places that have high levels of protection across borders are still having incursions of the virus still coming in.

“You’ve got to weigh that against what’s happening within the country – at the moment we’ve got tens of thousands of people being infected every day and so putting a lot of effort into preventing handfuls of infections from coming overseas has to be proportionate.

“It is a global problem, and if we remain globally connected, which I think we must, then it is about the rate and the risk of this happening rather than whether it does or not.”

We see these variants popping up variably all over the world, so we’re just as liable to suffer from a homegrown one as an imported one

Also on the issue of borders, Danny Altmann, professor of immunology at Imperial College, told Times Radio they presented a “really, really hard challenge”.

He added: “We see these variants popping up variably all over the world, so we’re just as liable to suffer from a homegrown one as an imported one. So we just need to be really on the case all the time.”

Asked about how worried people should be about the Brazilian variant, he said: “Somewhat worried, but not total panic, perhaps.

“It’s somewhat more worrying than the UK variant, the Kent variant, that we’re used to talking about, because it covers the double whammy, we think, of being more transmissible and somewhat better at evading neutralising antibodies.”

But Dr Deepti Gurdasani, epidemiologist at Queen Mary University of London, said the current situation in the UK “highlights failures in quarantine policy”.

She told BBC Breakfast: “Sage has advised that, unless we had a comprehensive, managed quarantine policy at our borders, something like this would happen.

“But unfortunately it’s something that we’ve been quite complacent about; now we’re just seeing the consequences of that.”

However, officials have said they remain optimistic that the Covid-19 vaccines will still prevent severe disease when tested against new variants.