The coronavirus reproduction number – also known as the R value – has risen above 1 across the UK for the first time since early March.
Here’s everything you need to know.
When was the data released?
New data released on Friday by the Government Office for Science and the Scientific Advisory Group for Emergencies (Sage) shows the estimate for R across the UK is between 1.0 and 1.2.
It comes as the number of newly diagnosed cases continues to rise, with higher incidence seen in young people aged 18 to 24 years.
When was the last time the R rate was above 1 across the UK?
According to Government advisers, the last time R was above 1 was in early March.
What does R represent?
R represents the average number of people each Covid-19 positive person goes on to infect. When the figure is above 1, an outbreak can grow rapidly.
In England, R is between 1 and 1.2.
Where is the R rate higher?
The figure is slightly higher in London and the North West – between 1.1 and 1.3 in both regions.
The estimates for R and growth rate are provided by the Scientific Pandemic Influenza Group on Modelling (SPI-M), a subgroup of Sage.
The growth rate of coronavirus transmission, which reflects how quickly the number of infections is changing day by day, has also increased slightly.
What are the R rates across the UK?
For the whole of the UK, the latest growth rate is between minus 1 per cent and plus 3 per cent per day.
The growth rate means the number of new infections is somewhere between shrinking by 1 per cent and growing by 3 per cent every day.
The most likely value is towards the middle of the range, experts advising the Government say.
But they also said R and growth rates are not the only important measures of the epidemic and should be considered alongside other metrics.
These include the number of new cases of the disease identified during a specified time period (incidence), and the proportion of the population with the disease at a given point in time (prevalence).
What are the R rates across England?
In the East of England, the R number is 0.9-1.2, while the growth rate is between minus 1 per cent and plus 4 per cent.
The R number in the Midlands is 0.9-1.1, while the growth rate in the region is between minus 1 per cent and plus 3 per cent.
In the North East and Yorkshire, the R value is 1.0-1.2, while the growth rate is between plus 1 per cent and plus 5 per cent.
In the South East, the R value in the region is 1.0-1.2, while the growth rate is between zero and plus 4 per cent.
The South West has an R value of 0.9-1.2 and a growth rate of between minus 1 per cent and plus 4 per cent.
In London, the growth rate is between plus 2 per cent and plus 4 per cent while in the North West, the figure is between plus 2 per cent and plus 5 per cent.