The whereabouts of that individual is unknown, as PHE says the person did not complete their test registration card so follow-up details are unavailable.
After pressure from Labour’s Yvette Cooper at a liaison committee a month ago, the PM said: “We are taking steps to ensure that we do not see the import of this new variant from Brazil.”
She wrote on Twitter today: “Cases of the Brazil variant now in the UK arrived a month after I first raised this issue with the PM. People travelled on indirect flights – an issue I also raised with PM that day. When it’s so important to protect vaccine programme, why has Govt been so slow to act?
“Delays bringing in measures like hotel quarantine have made it easier for Brazil variants to spread across UK. But even now 99% of arrivals aren’t covered by hotel quarantine as we heard this week. And notable that tests up to 72hrs pre-flight didn’t catch these cases.
“Three Scottish residents had flown to NE Scotland from Brazil via Paris & London” Repeatedly I’ve asked Ministers why not test travellers on first arrival in UK before they go home on public transport (tube/train/plane)? Why do they refuse to do this?”
She added: “We need to know urgently how all these cases have arrived in the country and why they weren’t prevented or picked up on arrival so that lessons can be quickly learnt and policies changed to protect the vaccine programme from further cases arriving.”
PHE and NHS Test and Trace are contacting the passengers on Swiss Air flight LX318 travelling from Sao Paulo, through Zurich, and landing in London Heathrow on February 10.
The Gloucestershire cluster was said to originate from one individual who travelled back from Brazil and arrived in London on February 10 – five days before the Government’s quarantine hotel policy came into force.
The remaining unlocated case is not believed to be linked to the others because the virus was found to have slight genetic differences.
Officials said their test was processed on February 14, so believe it is likely they took it a day or two earlier.
Shadow home secretary Nick Thomas-Symonds said the detection of the variant in the UK was “deeply concerning”.“It is now vital that we do everything we can to contain it,” the Labour MP said.
“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.”
Experts detected the new variant circulating in December in Manaus, north Brazil.
It is not yet known if the mutation causes more severe Covid-19, but evidence suggests it may be more transmissible.
Scientists are conducting analysis to establish if it has a higher mortality rate or if it affects the vaccines or treatments.
The variant was detected in Brazil and in travellers from Brazil to Japan, and contains a unique constellation of lineage defining mutations.
The P. 1 variant is associated with a surge of cases in Manaus late last year, which led to a severe second wave of Covid-19.
Scientists were concerned because this raised the possibility it is able more easily re-infect patients due to the mutations it carries. But the evidence for this is currently limited.
Professor Stephen Powis, the NHS’s national medical director, has said coronavirus vaccines can be quickly adapted to tackle new strains, following the emergence of the new Manaus variant which may respond less well to existing immunisations.
Public Health England (PHE) identified the first UK cases of the new potentially more transmissible variant on Sunday – three in England and three in Scotland.
Prof Powis told BBC News: “The new vaccines which are being used for Covid can be adapted very rapidly so it’s likely that if we do need to change the vaccine that can be done in months, rather than years, which was the case with the more traditional vaccines.”
Additional reporting by PA