Alfred Hitchcock’s 1935 original adaptation of the John Buchan novel about a good chap on the run from evil foreign powers has nothing to fear from this version although there is more to recommend it than Ralph Thomas’s 1959 version and it is generally regarded as the adaptation most faithful to the original text.
It starts off well enough, full of authentic-looking period locations and spy vs.spy skulduggery and the film looks like it might have some justification. But once John Mills as the British agent, Scudder, is killed off and Robert Powell as Hannay takes over his mission, things go rapidly downhill. Indeed there are so many ludicrous moments that the film has some comedic value, appearing at times as if it might have been directed by Basil Fawlty. Indeed it is difficult to decide whether David Warner as the arch -villain or Powell as Hannay are acting badly or are bad actors (Powell has a pretty solid CV in the latter department and his attempt here to appear drugged would tend to suggest the latter) whilst Karen Dotrice as the romantic interest (replete with soft-focus close-ups) makes for a perfect example of British neurasthenic unsexiness. All this gives the film a certain charm and if you like domestic British film-making of the 1970s this serves as a good example.
FYI: DIrector Don Sharp was a Tasmanian-born writer-director who worked extensively in British television from the 1950s to the 1980s