LONDON (Reuters) – Britain’s deputy chief medical officer said on Saturday he was confident the coronavirus “R” number, a measure of the rate of contagion, was below 1 across the United Kingdom.

“I am confident that our R is less than 1 overall,” Jonathan Van-Tam said at the government’s daily news briefing.

The R number, or effective reproduction number, measures the average number of people that one infected person will pass the virus on to. An R number above 1 can lead very rapidly to exponential growth.

(Reporting by James Davey and Estelle Shirbon; Editing by Alex Richardson)