Increased socialising in London since lockdown has caused its R rate to surge above 1, scientists have found.
The largest Covid-19 testing surveillance study revealed it is now 1.27 in the capital meaning that nationally falling infection rates have levelled off.
The REACT study by Imperial College London and Ipsos Mori swabbed 160,000 people in England between November 13 and December 2.
Prevalence rose in London from 98 per 10,000 people infected in mid-November, to 121 per 10,000 infected by early December.
Study lead Prof Paul Elliott said: “We do seem to be in a another period of quite rapid acceleration again.
“We do know from mobility data that things picked up over that latter period.
“We know how the virus is transmitted and that is through more close contacts.”
Nationally the reproductive number is was somewhere between 0.81% and 1.03% during the latest period between November 25 and December 3.
This suggests the R rate overall was slightly below 1 but this masks stark differences around the country.
The REACT study is not the official R number. That is compiled by government advisors SAGE based on many different studies at once.
There has been a large fall in the West Midlands. The most infectious age group is now secondary school pupils whereas a month ago it had been 18 to 24 year olds.
The average regional prevalence during lockdown compared with mid-October to beginning November was highest in Yorkshire and the Humber at 1.35%, down from 2.32%.
Talking about Christmas, Prof Elliott added: “Each family and each grouping really needs to take their own view.
“If there are vulnerable people in families, we know how this virus is transmitted and it’s through contact.
“Just because people can do it doesn’t necessarily mean in their own individual circumstances they should do it.”
