Thousands of workers in the government’s new test and trace call centre failed to trace a single contact of a coronavirus case in the first three weeks of operation.
Between them the 25,000 call handlers contacted a total of only 15,812 people to tell them to isolate.
The government says the system has contacted 114,000 people who may have been exposed to the virus.
But the vast majority of these were found by existing public health teams.
An investigation by BBC Panorama has discovered that 98,000 of the contacts were traced by only 870 public health officials.
The local officials work for Public Health England and are experts in contact tracing. They are responsible for managing more complex cases, like outbreaks in schools and care homes, which often reveal