The government is facing urgent calls for tougher border measures after UK officials said they were searching for one of six people infected with the highly transmissible Brazilian coronavirus variant. Public Health England said on Sunday that three cases of the variant had been detected in England and three in Scotland, but that the identity of one of those carrying the virus was unknown as they had not provided their contact details. The P1 variant, also known as the B1128 variant, shares some of the same mutations as the highly transmissible South African variant and was first identified in Manaus, Brazil, in January. It is thought that it could respond less well to current vaccines. Two of the English cases are from a single household in south Gloucestershire, a member of whom returned from Brazil a month after the variant was first identified and five days before the hotel quarantine policy came into force. One individual in the household is understood to have developed symptoms before getting a test. Their contacts have been identified and retested, but surge testing is being rolled out in the Bradley Stoke, Patchway and Little Stoke areas as a precaution. PHE and NHS test and trace are also following up with all passengers who arrived on the same Swiss Air Lines flight, LX318, which travelled from São Paulo via Zurich and landed at London Heathrow on 10 February. However, a third, currently unlinked individual is still being sought whose identity is unknown because they did not complete the registration card that came with their Covid-19 testing kit. Officials said their test was processed on 14 February, so it is likely they took it a day or two earlier. The person is unlikely to have taken their test at one of the regional test sites, where staff can check if contact details have been provided, but it could have been a home test or from local surge testing. “We are therefore asking for anyone who undertook a test on 12 or 13 February and hasn’t received their result or has an uncompleted test registration card, to call 119 in England or 0300 303 2713 in Scotland for assistance as soon as possible,” PHE said. It is also urging anyone on the Swiss Air Lines flight who has not been contacted to call 01174 503 174 to arrange a test. The quarantine hotel policy, aimed at protecting the UK against new variants came into force on 15 February after much delay. In Scotland all international arrivals must go into hotel quarantine for 10 days, while in England the rules only apply to arrivals from 33 “red list” countries. Nick Thomas-Symonds, the shadow home secretary, said: “It is deeply concerning that the Brazil Covid variant has been found in this country. “It is now vital that we do everything we can to contain it. But this is further proof that the delay in introducing a hotel quarantine was reckless and the continuing refusal to put in place a comprehensive system leaves us exposed to mutations coming from overseas.” Three people living in north-east Scotland have also tested positive for the P1 variant after returning from Brazil via Paris and London. They were identified while self-quarantining and have since completed their full 10-day isolation period. Other passengers on their flight, which landed in Aberdeen in early February, are being contacted as a precaution. This is the first time the P1 variant has been detected in the UK, although another Brazilian variant called P2 has previously been detected. Although it is currently being investigated, the early signs are that the P2 variant is not more transmissible. A report from Brazilian researchers said the P1 variant was “potentially associated with an increase in transmissibility or propensity for reinfection of individuals”. It is also possible the variant may respond less well to current vaccines, but experts say more work is needed to understand this. Dr Susan Hopkins, the PHE strategic response director for Covid-19 and NHS test and trace medical adviser, said: “We have identified these cases thanks to the UK’s advanced sequencing capabilities which means we are finding more variants and mutations than many other countries and are therefore able to take action quickly. “We ask that individuals come forward for testing through the symptomatic and asymptomatic test sites across the countries in order to continue to drive down cases in the community.” The Scottish health secretary, Jeane Freeman, said: “This new variant demonstrates how serious Covid is and reinforces the need to minimise the spread of the virus. We would encourage everyone across the country to adhere to the necessary public health restrictions by staying at home except for essential purposes as this is the single best way of staying safe and stopping the spread of this virus. It is now also illegal for anyone to travel to or from Scotland unless it is for an essential reason.” The chair of the Commons home affairs committee, the Labour MP Yvette Cooper, said the development showed the weaknesses in the government’s Covid border measures. “The Brazil variant was first identified a month before one of these cases was brought in on 10 February and many weeks after the prime minister was warned that indirect flights were a problem, yet the government delayed putting stronger measures in place.”