Health bosses are trying to track down a mystery Brit infected with the strain and Mr Hancock will make a statement on the matter at 1.30pm today.
His announcement will centre on the missing mystery British traveller infected with the Brazilian Covid strain.
Residents living in five postcodes have been urged to get tested for Covid after six people were found to have been infected with the mutant bug in England and Scotland.
Officials are also searching for passengers who were on the Swiss Air flight LX318 from Sao Paulo to Heathrow, via Zurich, which landed on February 10.
But the Health Secretary has defended the Government's border arrangements following the detection of the cases of the worrying Manaus variant.
Mr Hancock said yesterday: "All the evidence is that the five cases that we know about followed those quarantine rules and that, I hope, is very reassuring to people.
"There is no evidence that the sixth case did not follow those quarantine rules - we need to obviously get in contact with the person in question."
“The test was taken on February 12 or 13 and "we haven't seen any further knock-on transmissions in the data".
Dr Susan Hopkins, of PHE, said health bosses were tracking "very closely" the new Brazilian P1 coronavirus variant.
She said: "The current vaccines have not yet been studied against this variant and we will need to await further clinical and trial data to understand the vaccine effectiveness against this variant."