This is yet another popular (and good) entry in the "Carry On" series. Like JACK, CLEO and SCREAMING, it's a parody of a current film or fad in its case the box-office sensation that were the James Bond extravaganzas (in fact, it was the first of innumerable spoofs/imitations of that long-running franchise). Kenneth Williams (complete with funny accent) is more or less at his best here; accompanying him are Barbara Windsor (this proved to be her series debut), Bernard Cribbins, Charles Hawtrey, Dilys Laye (as a femme fatale), Jim Dale (playing the gang's long-suffering contact man) and Eric Barker (as, what else, their superior).
While it cleverly features an androgynous villain (played by Judith Furse and voiced by John Bluthal), the film also lampoons earlier classic British thrillers such as Hitchcock's 1930s efforts and THE THIRD MAN (1949). The action takes place in a variety of locales from a Viennese café to an Algerian harem; typical espionage elements are the gang's donning of various disguises to follow or elude enemy agents and the perilous train journey. By the way, the villains' headquarters are amusingly accessed via a public convenience which also pays off with an inspired surreal ending. In a direct nod to the Bond model, we get silly acronyms for the various organizations involved (such as S.T.E.N.C.H., S.M.U.T., S.N.O.G., etc).