1953, but no street kids here playing on bombsites. After a very brief start in the English countryside our boy hero is off to Gibraltar and soon investigating mysterious deaths of the Barbary apes, and uncovering a linked deeper terrorist plot against the Empire! He's helped by a terrific little local girl-Nati Banda-of whom there is absolutely no further information as to her career/life.
Of course, the adults don't believe, or are too busy, to listen to the children, who get involved in quite serious chases and other hairy looking escapades. Despite the (unintended?) comic relief of an incompetent baddy played by George Cole, the plot has a few nasty episodes, which must have been quite worrying to the young audience of the time.
The film has interesting shots of the underground complexes of the Rock and is also quite valuable as a record of the British Naval activities then, and, of course, the social customs and conventions.
What a treasure trove the CFF archive is.