The reproduction number, or R rate, of coronavirus transmission across the UK has risen to between 1.0 and 1.4, according to the latest government figures.
It represents an increase from the last estimate, on December 23, of between 1.1 and 1.3.
On Friday the Government Science Office (GSO) also published regional R numbers for different parts of England.
Regional R numbers across England, as estimated by the government science office
East of England 1.1 – 1.3 ( down from 1.2 – 1.5)
London 1.1 – 1.4 (down from 1.2 – 1.5)
Midlands 1.1 – 1.4 (up from 1.0 – 1.2)
North East and Yorkshire 1.1 – 1.4 (up from 0.9 – 1.1)
North West 1.0 – 1.4 (up from 0.9 – 1.1)
South East 1.1 – 1.4 (down from 1.2 – 1.4)
South West 1.1 – 1.5 (up from 1.1 – 1.2)
In Scotland the latest figures estimate the R rate is between 0.9 and 1.3.
In Wales the R rate is estimated to be between 1.0 and 1.3.
And in Northern Ireland it is estimated to be above 1.
R measures the number of people, on average, that each sick person will infect.
If R is greater than 1, the epidemic is generally seen to be growing; if R is less than 1 the epidemic is shrinking.
The estimate represents the situation over the past few weeks rather than a snapshot of the situation on Friday, due to the time delay between initial infection, symptoms appearing, and the need for hospital care.
More than one million people in England – or one in 50 – had coronavirus last week, separate figures from the Office for National Statists (ONS) suggest.
An estimated 1.1 million people in private households in England had Covid-19 between December 27 and January 2.
It comes as the UK recorded 1,162 more Covid-related deaths in the space of 24 hours.
Mayor Sadiq Khan on Friday declared a major incident in London due to soaring cases, with hospitals set to be overwhelmed in the coming weeks if the spread of the virus does not slow.