My Lords, last week’s figures suggest that 67% of people who tested positive for coronavirus were reached by our contact tracers. This figure is rising every week. The epidemiological logic is that a system such as “test and trace” will never be 100% ubiquitous or track everyone who carries the disease—asymptomatic infection is a part of this terrible disease. However, it can have a profound effect on its spread and break the chain of transmission. That is why we have invested in this infrastructure and why we appealed to the British people to comply with the isolation protocols.