Government figures put the so-called “R” rate — the reproduction number that shows how fast the virus multiplies — between 1.0 and 1.2, driven by a surge in cases among younger people. The virus is spreading exponentially when R is above 1.

A separate study by Imperial College of more than 150,000 people in England estimated the R number as 1.7 and found the virus is now doubling every seven to eight days…

The study by Imperial College and Ipsos MORI estimated that 13 people per 10,000 were infected between Aug. 22 and Sept. 7, compared to four people per 10,000 between July. 24 and Aug. 11.

It said Covid-19 cases were no longer clustering in care homes, as seen in May and June, suggesting the virus is now spread more widely in the community. Infections are increasing across all adult age groups below the age of 65, with higher rates seen in people aged 18 to 24. Infections are highest in Yorkshire and the Humber, the North East and the North West.