 Although Concorde had its first flight in 1969, it did not go into service until 1976.The original 25 minute episode is thought to no longer exist, making it the only "Goodies" episode which is officially lost; however, the expanded and more elaborate version for the 1972 Montreux festival is said to have only minor differences with its 1971 prototype.One difference is the ending; in the original the giant mice are represented by stock footage of real mice inserted into the footage using chroma-key (CSO).