Petty Officer Telegraphist Casey Brown was a member of Captain Keith Mallory's team on Navarone during World War II. Prior to the war, he'd been an installation and testing engineer at a yacht builder's yard. Despite his penchant with mechanical things, Brown was assigned to the Communications Branch by the Royal Navy. He served as the team's engineer, and was also a first class guerrilla fighter, having been in the Special Boat Service in the Aegean and Libya. On Navarone, he and the Greek resistance members Louki and Panayis created distractions so that Mallory and Corporal Dusty Miller could get inside the German fortress. When Louki was injured, Brown looked after him, sending Panayis, who he didn't know was a traitor, to go and get Mallory and Miller. In the meantime, Miller figured out Panayis was a traitor and killed him. After the American successfully destroyed the German guns which had been the group's target, Brown and Louki, along with Mallory, Miller and Andrea, were picked up and rescued by the Sirdar.
- In the film, Brown is a British Army private and not a Naval engineer. He served in the Spanish Civil war, where he earned a reputation for being a bloodthirsty assassin nicknamed "The Butcher of Barcelona." He was called "Butcher" Brown by his comrades in the military. Despite his nickname and reputation, he was actually a hesitant killer who ironically only used violence as a last resort. His reluctance to murder his opponents got the team in trouble numerous times, and ultimately resulted in his own death at the hands of a German sailor he hesitated to kill.