What operators wear in prison? (6)
I believe the answer is:
scrubs
I believe this is a double definition.
'what operators wear' is the first definition.
(surgeons were scrubs during operations)
'prison?' is the second definition.
(Wormwood Scrubs)
'in' is the link.
(Other definitions for scrubs that I've seen before include "special clothing for those working in the theatre" , "Abolishes" , "Cleans with hard rubbing" , "Wormwood _____" , "Protective garments for surgeons" .)