The Clue of the Missing Ape, aka Gibraltar Adventure, is a 1953 English childrens film largely set in Gibraltar. Directed by James Hill, it was produced by the Gaumont Specialised Film Unit, a descendant of the Gaumont British film studio. Players included veteran character actor George Cole.
Sutton and Ellis have the task of saving Gibraltar from this sinister attack. A series of chase scenes includes many of the key sights of Gibraltar as they existed in 1953, including the fortified spine of the Rock of Gibraltar and the Gibraltar water catchments.With the lastminute help of adults, the terrorist plot is foiled and the Royal Navy is saved. The films closing credits scroll to the accompaniment of Rule Britannia. ........
Source: Wikipedia