R represents the average number of people each person with Covid-19 goes on to infect - meaning if the figure is above 1, an outbreak can grow exponentially, but when it is below 1, the epidemic is shrinking.
The current R rate for the whole of England is between 0.7 and 1, broadly similar to last week’s figure of between 0.8 and 1.
An R number between 0.7 and 1 means that, on average, every 10 people with Covid-19 will infect between 7 and 10 other people.
However, government scientists have estimated that R could be above 1 in London (where the rate is between 0.8 to 1.1) and the South West (0.7 to 1.1).
The full list of estimated R rates for England are below:
East of England (0.7 to 1.0)
London (0.8 to 1.1)
Midlands (0.7 to 1.0)
North East and Yorkshire (0.7 to 1.0)
North West (0.6 to 0.9)
South East (0.6 to 0.9)
South West (0.7 to 1.1)
The Scientific Advisory Group for Emergencies (Sage) notes that if a region’s estimated R rate is within a range that exceeds 1, it “does not necessarily mean the epidemic is increasing in that region, just that the uncertainty means it cannot be ruled out”.
It also acknowledges that the R rate becomes harder to measure when cases, hospitalisations or deaths are low.
The data came as figures from the Office for National Statistics (ONS) suggested that Covid-19 infections across all parts of the UK had fallen to the lowest level since autumn 2020.
About one in 480 people in private households in England had Covid-19 in the week to 10 April, down from one in 340 in the previous week, according to the latest estimates from the ONS.
Meanwhile in Wales, about one in 920 people were estimated to have had coronavirus in the week to 10 April, down from one in 800 in the week before.
These figures are the lowest level for England and Wales since September.
Both figures are the lowest in the two countries since estimates began for the nations in October.
Additional reporting by PA