LONDON (Reuters) - British Prime Minister Boris Johnson defended the national test and trace system on Wednesday, saying it was yielding “granular detail” on the incidence of coronavirus cases so ministers could put in place measures to stop the spread of the virus. Asked why he had said earlier that the system had very little to do with the spread of the disease, Johnson said: “One of the great advantages of NHS (National Health Service) Test and Trace ... is that we now have the ability to see in granular detail where the epidemic is breaking out. “That’s why we’ve been able to deliver the local lockdowns and that’s why we’re able to tell now at this stage it is necessary to take the decisive action that we are,” he said, referring to the government’s implementation of stricter restrictions to try to stem the spread.