Fewer than one in six Lambeth residents have heeded a call for everyone who lives and works in the borough to have a PCR test for COVID-19.
The so-called 'surge testing' was launched earlier this month after a number of cases of the variant first identified in South Africa were detected in Lambeth and neighbouring Wandsworth.
The council said on Saturday that those who have not been able to participate so far are asked to take a PCR COVID-19 test by the end of Monday.
More than 50,000 people in Lambeth have taken a PCR test over the last 12 days, but residents and workers can still join this important initiative by visiting a local testing site, ordering a test online at gov.uk or by calling 119.
With Lambeth's population standing at more than 300,000, this means that the vast majority of residents have failed to heed the call so far.
Ruth Hutt, Lambeth's Director of Public Health, said: "Thousands of people in Lambeth have joined this enhanced testing operation in Lambeth and we are incredibly grateful for their contribution.
"Enhanced testing will continue until the end of Monday – so I would urge anyone who hasn't taken a PCR test yet to please join in.
"It is important to add, that as well as taking a PCR test, residents should continue to follow the current guidance which includes limiting your number of contacts, washing your hands regularly and thoroughly, keeping your distance and covering your face.
"If you test positive for Covid-19 you must isolate in order to prevent passing on the virus."
Full details of the site locations and instructions have been published on the council website at www.lambeth.gov.uk/enhancedtesting
In the north of the borough, the test centre at St John's Waterloo is closed at weekends. Temporary testing facilities are available daily at Jubilee Gardens and outside the Royal Festival Hall.
Online PCR test kit ordering for those who are unable to access a testing site is also available via www.gov.uk/get-coronavirus-test
Lambeth residents should select the option "my local council or health protection team has asked me to get a test, even though I do not have symptoms" when asked why they are requesting a test.
Test kits have also been distributed via all Lambeth secondary schools.
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