 "The Inquisition" is the only episode of "Captain Scarlet" in which Colonel White and Cloudbase (excluding the Mysterons' simulation) do not appear.The exterior of the Markham Arms was designed as a Tudor-style pub by Mike Trim and built as a cardboard and Perspex scale model by Alan Shubrook.To give the model an aged look, Shubrook used sandpaper to wear down the walls and applied strokes of dark paint around the windows to give the impression of rain stains.