“This is growing very fast with a growth rate of initially two to three days, and that growth rate seems to be shortening rather than lengthening,” Dr Susan Hopkins said.

“We are concerned with the large volume of individuals who are being infected every day in the population that we are going to have a very difficult four weeks ahead with cases in the community,” she said.

“We are seeing a higher rate of reinfection than we’ve seen before,” Hopkins said.

Hopkins said infection from one variant of coronavirus should protect against severe disease from another variant, but it may not protect against mild disease or from transmission of the virus.

Asked if an infection from the Omicron variant could bolster immunity against the Delta variant, she replied: “There will be protection, I think, from severe disease if you’ve had one variant or the other, but these new variants may not protect you from mild disease. And may not protect you from transmitting to others.”