Contact tracing
We spoke to journalists around the world and experts to find out.
Another week, another set of figures going in the wrong direction.
Service fails to hit consistent 80% figure that experts say is needed to make system viable.
NHS volunteer responders across England will also take part.
Some 6,000 tracers will be redeployed to local schemes to try and identify more people carrying coronavirus.
The nation marked the milestone on Sunday, but leaders have warned against complacency as cases continue to surge worldwide.
Week after week, the service misses its targets on speed and effectiveness. Here's what's wrong with the government's flagship coronavirus programme.
Study finds schools can only reopen safely with scaled-up testing, contact tracing and isolation.
Former tracing chief says London would benefit most from the new tech.
Labour accuses government of failing to learn lessons of Carillion collapse.