1. So here's a discussion. False +ves and -ves are always with us. The higher they are the less informative a test will be about a specific case. When high, a Bayesian adjustment of likelihoods following a test result will tend to be muted, but adjustment there should still be. https://twitter.com/DamCou/status/1245893513050492929

2. Crucially, the main purpose of the CV19 tests is *not* to determine the appropriate treatment for an individual: it is to inform collective, public health decisions. In that context, the magnitudes of the false readings become much less significant.

3. If, say, the aim is to estimate the % of the population that is currently infected (and that's information that would be very valuable indeed for policy) by means of a randomized sample, and if it is estimated that an available test ...

4. … yields around 25% false -ves, you adjust the test % of +ves up by 33% to arrive at what will be a decent estimate for the population as a whole. For collective, public health decisions, it could be said that 'A poor test is better, (indeed a whole lot better) than no test'

5. Two closing thoughts:
(a) I currently have a sense that specious arguments are being dragged up in attempts to justify the UK delays in testing.
(b) When scientists are afforded power & influence they evolve into politicians. Call it the Animal Farm effect.