A brilliant London-based "consulting detective", Holmes is famous for his astute logical reasoning, his ability to take on almost any disguise, and his use of forensic science skills to solve difficult cases.
In the film, Holmes appears as the "neighbor" to Basil of Baker Street. He is the world's greatest human detective (Basil being the world's greatest mouse detective). While Basil, Dawson, and Olivia Flaversham look for Toby, they observe Holmes with Watson (depicted as silhouettes against the wall). The two depart the scene to continue their own investigations, allowing Basil and the company to "borrow" Toby in the meantime.
Sherlock Holmes' voice in The Great Mouse Detective is taken from clips of the original Sherlock Holmes films.