When filming the show, Michael Crawford had to perform scenes over and over in front of the extras and other actors, until they no longer seemed funny to the cast and crew. Even then, some takes were still ruined by someone giggling in the background at Frank's antics.
Michael Crawford performed all his own stunts. When performing stunts, he usually wore gloves, so if he suddenly appears wearing them, a stunt is usually about to follow. For this reason, there sometimes appear to be continuity errors (no gloves/gloves/no gloves).
The bridge that Frank Spencer famously roller skated down in one episode is at Edmonton Green in north London and is due for demolition in November 2004 as part of the redevelopment of the area. The rink he was skating at before going through the wall was at Pickett's Lock, nearby.
Michael Crawford was the third choice for the role of Frank Spencer. The part had been created for Norman Wisdom (based on the physical clowning, pratfalls and ineptitude of his "Gump" character), but he Had to turn it down due to other commitments . Ronnie Barker also turned it down. Dudley Moore was also considered for the role.