The mystery person who tested positive for the Brazilian Covid variant but could not be traced has now been identified, Matt Hancock has announced.
The so-called “Patient X” was tracked down to a residence in Croydon, south London, on Wednesday after a team of 40 public health officials combed the records of thousands of home test kits.
The individual is believed to have completed the mandatory quarantine after arriving in the UK and is not thought to have passed on the virus. However, in the interests of caution intensified testing and genetic sequencing are being ramped up in the neighbourhood.
Scientists say the Brazilian P1 variant appears to be more contagious and there are concerns that Covid vaccines may not be as effective against it.
Mr Hancock told a Downing Street news briefing: “Using the latest technology, and with the dogged determination of our Testing and Tracing scheme, we have successfully identified the person in question.
“The best evidence is that this person stayed at home and there is no evidence of onward transmission, but as a precaution we are putting more testing in in Croydon, where they live, to minimise the possibility of spread.”
Mayor of London Sadiq Khan urged residents in Croydon to “come forward” for a test. 
In a statement, Mr Khan said the Government’s delay in implementing a hotel quarantine system for international arrivals had been to blame for allowing the P1 variant, first identified in the Brazilian city of Manaus, into the country.
The capital’s Labour leader said: “It is good news that this person is now in touch with the authorities.
“To ensure we minimise the risk that this strain of the virus spreads further, public health officials in Croydon are now encouraging people to come forward for a test – and I urge residents to take one when offered, regardless of having symptoms or not.”
Six cases of the P1 variant, first identified in the Brazilian city of Manaus, have been found three in Scotland and three in England. A public appeal was made for one of those people in England to come forward after they took a test in February but left no contact details.
Earlier this week, Mr Hancock said the hunt for the infected person had been narrowed down to 379 households in the south-east of England. 
The three cases in Scotland were all oil workers returning to their families from Brazil, via Paris and London. Health officials have been trying to trace all the passengers who were on their flight from Heathrow to Aberdeen.
In England, two of the cases are from the same household in South Gloucestershire, who tested positive after someone had returned from Brazil on Feb 10.
It came as Public Health England revealed that it is monitoring a new “variant under investigation”, known as VUI-202102/04, 16 cases of which have been found through genetic sequencing.
PHE said the latest identified variant, also known as B.1.1.318, contains the E484K mutation, found in two other VUIs in the UK, but it does not feature the N501Y mutation that is present in all variants of concern.