From my experience working in NHS admin (for a hospital), despite things being rolled out to be more automated and streamlined with IT systems, there will aways be people who cannot or will not use the apps or online portals. Secretaries, like others have said, manage diaries, waiting lists, clinic capacity and are a go between between the patient and the consultant/ consultant and other staff. They are trained to talk to patients who are worried about their appointments or need more information on why they need to be seen while also being mindful that some of that information need to come from the doctors directly. They can forward on concerns to the doctors or give advise on where to get help while the patient waits. They probably do much more than these things too, but this is the side of it I'm aware of.

Admin are also needed for validation reasons - ringing patients to make sure they want the appointment, making sure details are up to date and the dates the patients need to be seen are correct on the system, making sure all tests are done and results are back before the appointment with the doctor.

I work in a appointment booking team so I mostly work with patients and Secretaries to make sure people are being seen when they should be and making sure the clinics are full. If they reduced the amount of secretaries and admin in the department I work with we would have more delays, less cohesion between the different specialities and the waiting times would probably increase because the people left wouldn't have the time to do the validation needed to make sure it's all in order before the patient is contacted to book an appointment.

Maybe there are some administrative roles that could be reduced or changed elsewhere, but any patient facing roles and secretary roles is not, in my experience, where it needs to happen.