Filming commenced with the pilot in May 1968 with the aim to shoot a 48-minute episode over a fortnight working Monday to Friday from 8:30am to 5:30pm with some filming on alternate Sundays. The bulk of filming with the main cast was on two sound stages at ABC Elstree in Borehamwood where "Department S" and other series were also in production. Establishing shots would use library footage. Location sequences were usually filmed by a second unit using stand-ins or the guest cast who were only needed for one episode filmed by one director while the main cast were completing the previous episode with another director. To keep costs down, a simple jump cut was used to make Marty Hopkirk disappear and reappear. Walking through walls was costly and time consuming using an image reflected on plain glass at an angle in front of the camera often used in the theatre called Pepper's ghost.