The eVisa system launched on 1st Jan 2025 (https://righttoremain.org.uk/update-on-evisa-transition/).

I misread a thing. Actually the system went into force at the border in February — that is when people have only been using their eVisas instead of alternative methods, as it's when the border switched to using the readers.

The government did not even stop issuing physical visa stickers until the beginning of last month.

So again, this ten million figure does not seem to indicate a likelihood of massive, systemic failure.

If there has been massive failure, then I guess the government department and the two US tech multinationals (Accenture's global HQ is only in Dublin for tax purposes) will have to figure it out.

It's older than that. It started in 2018. January 2025 was when the system became eVisa only.

In this case I suspect that either there was a recent mix-up or that person hasn't travelled since she came to the UK or got settled status and never noticed the problem.

EU citizens in the UK since before Brexit only got an eVisa when their status transitioned to "Settled status" for instance and never had anything in their passports. But as long as their online account is up-to-date (i.e. linked to current passport) they can even use the automated passport check gates on arrival into the UK. Only issue since ~last year and especially now that ETA is mandatory for non-residents is to prove status to airline staff on departure otherwise they deny boarding, this is done through online account.