One case of the new Omicron variant of coronavirus has been identified in Brentwood in Essex, the government has confirmed.
The UK has introduced travel restrictions with a number of southern African countries, including South Africa and Botswana, after the new strain was identified this week.
The Department of Health and Social Care (DHSC) has revealed another case of the variant has been found in Nottingham.
Both of the cases are believed to be connected and linked to travel to southern Africa.
The individuals that have tested positive, and all members of their households, are being re-tested and told to self-isolate while further testing and contact tracing is under way.
It was initially reported that the Essex case had been identified in Chelmsford, but the location was later clarified following an update from the UK Health Security Agency.
A spokesman for Essex County Council said: "We can confirm that a single case involving the new Covid-19 Variant of Concern (B 1.1.529), Omicron, has been identified in Brentwood.
"This is linked to a single case from Nottingham involving international travel to South Africa.
"We are working with regional and local public health officers who are assessing the situation.
"All close contacts of these individuals will be followed up and requested to isolate and get tested.
"The individuals who have so far tested positive, as well as all members of their households, are being re-tested and have been told to self-isolate while contact tracing is under way.
"While this work takes place, it is important that everyone takes sensible precautions – get a PCR test if you have symptoms, isolate when asked, wear a face-covering in crowded and enclosed spaces, ventilate rooms, get your vaccine and boosters as soon as you can."
A spokesman for DHSC said: "The UK Health Security Agency is carrying out targeted testing at locations where the positive cases were likely to have been infectious.
"In response to the developing situation, the UK is taking decisive action to protect public health. Confirmed cases and contacts are being followed up and requested to isolate and get tested as necessary."
Suffolk MP Dr Dan Poulter has warned measures such as wearing face masks in shops may be brought back if the new variant spreads throughout the UK.
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