 This footage includes scale model shots of the Spectrum Detector Trucks, which were designed by special effects assistant Mike Trim.The puppet-scale interior of the trucks was adapted from the "Zero-X" Martian Exploration Vehicle cockpit that was originally built for the film "Thunderbirds Are Go" (1966) and last seen in "The Mysterons".Paul Cornell, Martin Day and Keith Topping, authors of "The Guinness Book of Classic British TV", consider "Manhunt" to be one of several "Captain Scarlet" episodes that "seem little more than left-over "Thunderbirds" scripts".