Last week, it was between 1 and 1.1. 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 exponentially but when it is below 1, it means the epidemic is shrinking.
An R number between 1 and 1.2 means that, on average, every 10 people infected will infect between 10 and 12 other people.
Meanwhile, the Delta Covid variant, initially found in India, has begun spreading in schools and colleges in England, according to Public Health England data.
The data, covering 26 April to 30 May, showed 140 cases of the Delta variant in schools. Prof Christina Pagel, director of University College London’s clinical operational research unit, told the Guardian the figures were evidence that schools were now “a major source” of transmission”.
Follow the latest updates below