It would be interesting to know how much of Inspector Hornleigh features Gordon Harker (playing Inspector Hornleigh) on screen. While Harker does get a fair amount of the running time, a lot is spent on his sidekick, played by Alastair Sim, and the villains.
The script’s approach to narrative drains the mystery from the film. The mystery is solved at the end, but it’s a mystery the ending itself raises. It’s supposed to be a twist, but the film’s gone on so long (and it runs under ninety minutes) and made all the characters so unlikable, it doesn’t really matter anymore. It’s not even a particularly interesting investigation.
But then there’s Sim. Sim has this endless comedy sequence (it’s probably five minutes), where he bumbles around. It’s kind of amusing, Sim’s good and all, but it’s pointless inserted into this light police procedural. The approach to Sim’s character is strange overall. He’s a moron, but Harker’s star inspector brings him along… and spends all his time not just ridiculing his intelligence, but his Scottish heritage. Inspector Hornleigh does not think highly of foreigners–Scots are dimwits and the Irish and Greek are evil.
The supporting cast has ups and downs. Steven Geray (a Hungarian) plays a Greek villain with a poor Peter Lorre impression. Edward Underdown and Hugh Williams are a tad bland. Gibb McLaughlin and Ronald Adam are both fine.
Harker and Sim are able to keep the film afloat for a while, but they tire by the end.