Passengers wait in line at the Eurostar terminal at St Pancras International Photo: Hannah McKay/Reuters

South Africa’s health department said last week that a new genetic mutation of the virus had been discovered and might be responsible for a recent surge in infections there.

“Thanks to the impressive genomic capability of the South Africans, we’ve detected two cases of another new variant of coronavirus here in the UK,” Hancock told a media briefing on Wednesday.

“Both are contacts of cases who have travelled from South Africa over the past few weeks.”

The United Kingdom is already trying to curb the spread of a separate mutated strain of the virus discovered in the UK which could be up to 70 per cent more transmissible, with further studies being carried out.

“This new variant [from South Arica] is highly concerning, because it is yet more transmissible, and it appears to have mutated further than the new variant has been discovered in the UK,” he said.

Susan Hopkins from Public Health England said the new variant in the UK “is very different to the variant in South Africa, it’s got different mutations.”

“Both of them look like they’re more transmissible. We have more evidence on the transmission for the UK variant because we’ve been studying that with great detail with academic partners. We’re still learning about the South African variant.”

She expressed confidence that vaccines that have already been developed should be effective “because the vaccine produces a strong immune response and it’s broad and acts against lots of variation in the virus”.