Additional testing is to be rolled out across part of west London after a “small number” of new cases of the South Africa coronavirus variant were found.

The Department of Health and Social Care (DHSC) on Thursday said additional testing and genomic sequencing is being deployed in Ealing as part of measures to monitor and suppress the spread of the virus.

Positive cases will be sequenced for genomic data to help increase understanding of Covid-19 variants and their spread, it added.

People living in the borough are “strongly encouraged” to take a Covid-19 test when offered.

The department said: “Working in partnership with the London Borough of Ealing, additional testing and genomic sequencing is being deployed within the borough, where a small number of additional cases of the Covid-19 variant first identified in South Africa have been found.”

It is the latest deployment of surge testing in England in a bid to control and suppress the potential spread of variants.

It comes as new Test and Trace figures showed 84,310 people tested positive for Covid-19 in England at least once in the week to February 17 – down 21% on the previous week and the lowest number since the week to September 30.

Some 86.8% of people who were tested for Covid-19 in England in the week ending February 17 at a regional site, local site or mobile testing unit – a so-called “in-person” test – received their result within 24 hours.

This is up slightly from 85.4% the previous week, and is the highest figure since the week to July 8.

Prime Minister Boris Johnson had pledged that, by the end of June 2020, the results of all in-person tests would be back within 24 hours.

Of the 83,000 people transferred to the Test and Trace system that week, 87.9% were reached and asked to provide details of recent close contacts.

The new figures also showed that 1,756,402 lateral flow device (LFD) tests for Covid-19, or rapid tests, were conducted in England in the week to February 17, down from a record 2,401,651 the previous week.

The DHSC said the drop coincided with school half-term holidays.

LFD tests are swabs that give results in 30 minutes or less, without the need for processing in a laboratory.

There were 1,116,433 polymerase chain reaction (PCR) tests conducted in the week to February 17. PCR tests are swabs processed in a laboratory.

This is the fourth successive week in which more LFD tests were conducted than PCRs.