Officials in the UK are racing to contain an outbreak of the COVID-19 variant first identified in South Africa that is now spreading through London's suburbs. 

More than 650,000 people have been told to take a PCR test, a more sophisticated coronavirus test processed in a lab.

It's the largest "surge testing" program carried out in the country so far, resulting in thousands of people lining up for tests.

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Director of Public Health at Lambeth Council, Ruth Wallis, said: "We think all our control measures we've put in place will work against the variant, but what we don't know is whether the transmissibility will be similar to or different from the one we found in the Kent variant at the end of last year.

"We have a vaccine program rolling out at pace and we want to make sure it is resilient to any variant that might crop up now and in the future."

Everyone over 11 years old who lives, works and travels through the area has been told to get tested.

The fear is that if the variant spreads across the UK, it could derail the country's vaccination program. But early studies suggest vaccines provide some level of protection against severe illness caused by it.

Patricia, a resident of Lambeth in South London, said it's "slightly worrying if the South African variant takes hold in Lambeth, and hopefully it hasn't."

Linda Redford, another resident, was collecting a COVID-19 test for her and her daughter. She said: "I've been vaccinated twice so I feel quite protected, but I was alarmed because there are a lot of vulnerable people in Lambeth."

Meanwhile a study by Oxford Vaccine Group is looking at mixing different types of vaccines to find out whether a combination of jabs for the first and second doses will give the recipient longer immunity.

It has already enrolled 800 people, and is now calling for another 1,000 volunteers aged over 50 to join the trial.

All this is happening as England emerges from lockdown this week, meaning shops, gyms and outdoor dining are now open. 

But there's plenty of concern that a new variant could drive the country back indoors.