Researchers compared data for nearly 55,000 pairs of participants who tested positive in the community – rather than in hospitals – between October and January and followed them for 28 days.

Initially British experts said evidence suggested the new strain was between 50% and 70% more transmissible, but the government later said it could also be 30-40% more deadly.

But the positive news was tempered by the finding that there was a sixfold reduction in the level of highly-potent neutralising antibodies produced against the South African variant.

The country is struggling with the worst Covid-19 epidemic in Southeast Asia.