Nessie was a Toho co-production with the British film studio, Hammer, famous for their horror films from the 1930s onwards. The film was first proposed back in 1976, but delays kept pushing it back until it ended up being a project for 1978, with an advance poster already created. Although some reports point that the film might have still been in production as late as 1979 before the movie was finally scrapped.
Work on the film had actually already commenced on Toho's part by the time that the financial backing from Hammer fell through. Special effects guru Teruyoshi Nakano had already designed and created the Nessie prop by the time the project was finally axed. This wasn't the first time a co-production between Toho and a foreign company resulted in one of the companies pulling out after production had started though, the first being the TV version of Varan in 1958. However, after the rights issues involving another failed joint venture, Latitude Zero, following its initial theatrical release, this project was most likely best deemed left unfinished. This film wouldn't mark the end of the Nessie prop, however, as special effects director Nakano would bring the creature back as the Dragon in his last film, Princess from the Moon, done in 1987. Also, Nessie would appear in Godzilla: The Series as one of Godzilla's allies.
The cast from the project, as stated on the poster, are Bryan Forbes as director, Teruyoshi Nakano as special effects director, David Frost, Euan Lloyd, Michael Carreras, and Tomoyuki Tanaka as producers.