Thanks to Brenda Steele for alerting me to this:

In the British Medical Journal on 27th April:

A leading statistician has criticised the UK government’s daily reporting of covid-19 swab test results, saying that no inference can be drawn reliably and that the failure to report by sample date could lead to serious misrepresentation of the pattern of the epidemic.

“The UK’s data collection and reporting of swab testing is a travesty of statistical science, as you can draw no inferences whatsoever about the evolution of the epidemic,” said Sheila Bird, former programme leader at the MRC Biostatistics Unit, Cambridge Institute of Public Health. “Politicians only seem to be interested in the number of tests performed rather than what is actually happening in the epidemic,” she told The BMJ.

Professor Bird goes on to point out:

This basic demographic information is already collected in Scotland, as all swab tests have an associated community health index number (CHI number), which includes the year of birth and sex of the person tested. Bird said that the CHI numbers used in Scotland enabled more helpful analysis because serial tests for the same person were readily linked.