The comic duo of Gordon Harker and Alastair Sim make "Inspector Hornleigh" an entertaining and watchable light mystery story. The plot itself has a couple of good touches - for example, getting good mileage out of a pair of similar briefcases - but it is the two main actors who make the film worth watching.
Harker (who plays Inspector Hornleigh) began his career with good supporting roles in three of Alfred Hitchcock's silent movies, and had a good sense of comic timing that he puts to good use here as the inspector in charge of a baffling case. Sim was an idiosyncratic, entertaining character actor who is best known for his wonderful portrayal of Scrooge in the 1951 version of "A Christmas Carol". Here he is Sgt. Bingham, the Inspector's earnest but inept sidekick, a good role for his distinctive talents.
"Inspector Hornleigh" is fairly routine as a mystery, but it is made very watchable by this entertaining comic pair who work well together. It is little known today, but in its time it was considered good enough that it led to two sequels. It is worth seeing if you like mysteries with some comic touches.