SAGE testing strategy document Aug 31st.
https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/914931/s0712-tfms-consensus-statement-sage.pdf
It includes a good description of the issues with PCR, but not solutions. Have a look at Scenario 2, p11. When virus prevalence is as low as it is, with a false positive rate where I think it is (around 1%, may...

...be more, upwards of 99% of the positive tests are false positive. They could easily slash this FPR by re-testing positives. That’s in this doc, too. But they’re not doing that but, instead, running full throttle, a knowingly flawed test, creating thousands of false positives.

Come on, SAGE, tell me why it isn’t a wholly reasonable conclusion that the vast majority of positive PCR tests are false positives?
Have you noticed that no one seems to be ill? You’re given pap about the young. In France, all ages have the same positive rate as the young.