How would YOU process a person with no ID, no papers, no passport, who you know absolutely nothing about. You don’t know their age, their nationality, whether they have a criminal background, whether they have any diseases, etc etc. Where would YOU start?
I’d start, as Assessing staff do, and have done for many years, by acting in accordance with the almost 100 page guidance (now two Guidances, one for pre-2022 applications, one for 2022 and years ff) for processing asylum claims, which explains in detail the stringent tests and benchmarks for plausibility and credibility for undocumented (and indeed for documented) asylum seekers.
I have no idea why some people don’t seem to understand that this is not a new issue, or that there are processes and systems, as well as is considerable experience and expertise in the government both within the UK relevant overseas departments, in dealing with it.