Its crossed my mind, but im presuming mail testing was the quickest way for the UK to set up an infrastructure and balance resources. Perhaps maybe a joint approach of the mail testing and centers locally might be the way forward. We have testing and contact tracing teams wholly over here. I suspect there are different challenges for the UK though, as we have a smaller population and country and not quite as big as an island.
The concern i have with mail testing is the efficacy for the reasons i mentioned earlier mate, in terms of people doing it themselves. My second concern is the timeline. How long does it take, presuming Joe Public has done it properly 1. Get a test after having symptoms, 2. Post it back. 3. Have it processed at labs, 3. Have it analysed. 4. Get the results. 5 Contact trace. Seems like a long time line to me and an inefficient way of contact tracing and identifying clusters (more then three linked cases).
For example, if i work in health care, i work on a ward were covid is present, i develop symptoms, i apply for a test, it arrives three days later, i do the test, i send it off, three days later it arrives at a lab, two days later its processed by the team, the results are recorded, the next day i get the results. You might be touching two weeks beginning to end, i might have recovered, gone to hospital. But critically i may live with my partner, parents, have been to work in a hospital, down the shops etc. while i have been a symptomatic during incubatition or - i may have infected others in the intervening periods over the lag, the whole process and timeline doesn't seem to lend itself to speedy contact tracing or shutting down clusters the same way immediate testing would in a testing center.
But im sure this has all be weighed and any testing system is better then none, the scale if it comes of is impressive, but testing also has to be purposeful beyond numbers. What is the reason you are testing? and What are you trying to achieve? - these are key questions. Is it to see how many people have the virus representativly, is it a knee jerk political seen to be doing - also keep their political promise during the crisis., or is it to shut down clusters and turn the tide in the community - speed and efficacy are the key factor in that. So its an interesting question as to why the UK government decided that this was the best approach for them and what were the reasons for that.