On Thursday, 3 June 2021 at 21:21:37 UTC+1, NY wrote:
I was impressed when my wife called in an accident while we were driving on
the A1 a few years ago. The emergency operator didn't need to be told where
we were and said "ah yes, I can see you've just passed the turning to Kirk
Smeaton, heading north". The phone had its GPS turned on (we were recording
a track on Viewranger) so I wonder if the location is automatically passed
to the 999 operator if GPS is enabled.

Yes, it's called Advanced Mobile Location (AML). It's been supported in the UK for a number of years now as BT (who run the first line operator assistance centres) were one of its developers.

Google's implementation (in Android) is called Emergency Location Service (ELS) and there's a bit of info about how it works he

https://crisisresponse.google/emerge.../how-it-works/