How likely is a false positive from a Covid test?

Positive thinking

The government wants us to test ourselves for Covid-19 twice a week, using lateral flow kits which will be freely distributed. What is the risk of being ordered to self-isolate as a result of a false negative?

— While the NHS claims that these tests produce false positives in 0.1% or fewer cases, an evaluation by Porton Down and Oxford University last year found a false positive rate of 0.3% in a hospital setting, rising to 0.39% in the community — in other words, about one in every 256 tests.

— According to the Office for National Statistics infection survey, in the week to 27 March one in every 370 people were infected (not necessarily showing symptoms) — 0.27% of the population.

— So for every 2 people who really do currently have the virus, you would expect 3 false positives.

Balance of power

The government set a target for 600,000 domestic heat pumps a year to be installed between now and 2028.