Video report by ITV News Science Editor Tom Clarke
Extra surge testing is to be carried out in several places across England in order to find cases of the South African variant of Covid-19.
Norfolk, Southampton and Surrey as well as an expanded area of Manchester will get extra testing to try and stamp out the variant of concern.
The surge testing will be carried out within targeted areas of the IP22 postcode, as well as the SO15 and GU22 postcodes.
Several areas of Manchester were already being offered surge testing after the discovery of the South African variant a few weeks ago.
The new expansions will cover specific areas within the M40 and M9 postcode.
The South African variant of Covid-19 is more infectious than the normal strain with very early research suggesting some of the vaccines may be less effective against it.
A study has suggested the Oxford/AstraZeneca vaccine was less effective at preventing a mild version of Covid-19 caused by the variant.
People living within the targeted areas are strongly encouraged to take a Covid-19 test this week, whether they are showing symptoms or not.
People with symptoms should book a test in the usual way while others should visit their council website.
The government did not reveal how many new cases of the South African variant had been detected in the areas being offered surge testing.
The latest data shows there are now at least 170 known infections of the South African variant in the UK, but figures are lagging and experts warned it was “very possible” it is already quite widespread in the UK.
The government said it had completed surge testing in parts of Haringey, Merton and Sefton, and would make the results available soon.
Surge testing was made available in some parts of south London last week after the South African variant was detected there.