I’ll always feel that Basil Rathbone remains the definitive Sherlock and Nigel Bruce is the only possible Watson, though I don’t believe anyone should stop attempting to portray them. John Neville and Donald Houston give acceptable performances as the detective pair in this instance. Their mission involves unraveling a massive criminal puzzle: uncovering the identity of "Jack the Ripper." The production quality is high, successfully recreating the atmosphere of Victorian Whitechapel with its active social scene and women described as being of questionable virtue; it has a slight resemblance to films from “Hammer” Studios. I felt that the large number of actors involved lessened the impact somewhat. There are simply too many characters—aside from Anthony Quayle, they mostly just added unnecessary elements to the narrative. The script is adequate and attempts occasional humor, but it’s often overly verbose, providing too much description and limiting our chance to participate in the investigation alongside them. It's an enjoyable film, a plausible imagining of events, but Neville doesn't quite capture what I consider to be Holmes—my apologies.

Source on TMDB