Below the line expenses and personnel are those which serve to physically produce the film or television episode. Most of the people who work behind the scenes — make-up designers, production designers, grips, gaffers, sound designers, visual effects designers, extras and many, many more —are "below the line crew". The leader of the below the line crew is, on many productions, the line producer. However, in Doctor Who history, line producers haven't often featured, outside of the Steven Moffat era. At least on the majority of BBC Wales DWU episodes, the de facto below the line head has been the production manager.