British scientists are trying to establish whether the rapid spread in southern England of a new variant of the virus that causes Covid-19 is linked to key mutations they have detected in the strain, they said on Tuesday.

The mutations include changes to the important “spike” protein that the SARS-CoV-2 coronavirus uses to infect human cells, a group of scientists tracking the genetics of the virus said, but it is not yet clear whether these are making it more infectious.