Surge testing has been deployed across south London after the South African variant of coronavirus was detected in a number of boroughs.
A total of 44 confirmed cases and 30 probable cases of the B.1.351 variant have been discovered across Wandsworth and Lambeth.
It is the UK’s largest surge testing operation to date, with residents of both boroughs encouraged to get a test regardless of whether they have symptoms.
All patients confirmed as having the variant of the virus are either currently self-isolating or have completed their quarantine, and all of their contacts have now been traced and asked to isolate.
Everyone over the age of 11 in Wandsworth and Lambeth has been advised to take a PCR test to determine whether or not they have the virus, with a number of pop-up testing facilities likely to be deployed.
Dr Susan Hopkins, chief medical adviser for NHS Test and Trace, said the cluster of cases is "significant".
"It's really important people in the local area play their part in stopping any further spread within the local community," she said.
Surge testing was rolled out across Wandsworth last month after a number of South African variant cases were reported which could not be traced back to international travel.
The South African variant was also detected in Lambeth in February, which led to surge testing across three postcodes.
Surge testing was announced on Sunday evening in Hillingdon, when the council confirmed that a single case of the South African variant had been detected.
“Although this was only a single case, it’s important that we take robust action to better understand the extent of this variant in the community,” said Hillingdon council leader Ian Edwards.
“PCR testing is now available for all and I would strongly encourage everyone, whether they live, work or travel through the boroughs, to get tested even if they don't have any symptoms of coronavirus."
“Understandably, some people may be concerned but there’s no reason for alarm and I would like to encourage people living and working in the identified area to get their test as soon as possible.”
The Department for Health and Social Care said it is the "largest surge testing operation to date", aimed at suppressing any possible new cases of the variant.