Many of the clerical staff are not directly involved with patients but are vital to a hospital. Finance teams manage payment for drugs and pay the rest of the staff. Claim back the cost of treating non nhs entitled patients, Estates staff organise repairs and maintenance, a lot of staff are employed to monitor compliance with government targets and work in the background resolving problems and coordinating appointments, reminding teams when target breaches could happen, secretaries, legal teams, stores teams, catering clerks send out menus and work with kitchen staff, then medical records, support for chaplaincy.etc etc.... a lot of these staff are paid on band 2 Or 3. Less than comparable jobs in the private sector.
Take them away and most of the coal face services couldn't function. Imagine a ward with no medical supplies, and when no one was recruiting and paying the nurses doctors and therapists. Where no one was sending a chap to unblock the toilet during an outbreak of diarrhoea.... just saying....