In message , Paul Corfield
writes

And also the fact that every instance of people being overcarried into
sidings or depots has to be reported to the HMRI (following the death at
Liverpool St? when someone was carried into the sidings). Hence there
have to be people specifically allocated to make sure this happens where
"reversals" are scheduled.

An S-Board at the headwall indicates to the driver that station staff
are available to help with detraining.
If one SA is available he/she starts at the back and meets the driver in
the middle. If there are two of us, it can be done in under two minutes.
(Depending how co-operative the passengers are)
--
Kat Me, Ambivalent? Well, yes and no.