A registrar is a doctor who is receiving advanced training in order to become a consultant. There is one registrar currently working at Holby ED. Registrars are required to wear scrubs while at work. These are generally a dark green colour, the same as consultants and junior doctors, although it may be a choice as Caleb Knight wore grey, as did Will Noble during his tenure as a paediatric registrar. Lily Chao wore what appeared to be her own clothes.