A PCR test may be the “gold standard” for clinical diagnostics, but it is not an appropriate tool for infection control mass screening.

The following extracts are from Rapid Tests Org https://www.rapidtests.org/. While presented in the context of US public health, the arguments are just as relevant to the UK.

Research from Harvard and Yale shows that:
Turnaround time is far more important than sensitivity.
Frequency of testing is far more important than sensitivity.
Screening with rapid tests can keep infections close to zero, even if the tests are less sensitive. A slower protocol cannot.

The type of rapid tests that could fundamentally control the virus have faced regulatory roadblocks. While some rapid tests have been approved, they typically require a prescription, and most require expensive and unscalable equipment. To control the virus, we need tests that can be easily mass produced, and which can be evaluated by anyone. The technology for such tests exists, but it is currently not approved because it does not meet strict diagnostic criteria.

Diagnostic criteria are inappropriate for a public health pandemic. When it comes to routine screening, we do not need the diagnostic capabilities of PCR, which can detect remnants of RNA well after a sick person has stopped being contagious. We need a simple test that detects when people are contagious and which can return results immediately.

We need to aggressively invest in all types of rapid tests. But we should especially invest in simple paper strip tests that can be produced in the vast quantities needed for frequent testing. Companies could be making these simple tests at tens of millions per day but are choosing not to because they are uncertain about regulations and are not getting up front investment from the government.