| Lloyd | Baxter | Tallahassee's owner. |
| Paul | Crachet | Catherine's partner. |
| Catherine | Dodd | The detective constable. |
| Pamela Jane | Evans | Gerard's assistant. |
| Doctor | Force | Martin's mystery companion. Aka: White-Beard, Adam Force. |
| Black-Mask | Four | The mystery man who attacked Gerard. |
| John | Hickory | Gerard's worker. |
| John | Irish | Gerard's worker. |
| Priam | Jones | A horse trainer. |
| Marigold | Knight | Bon-Bon's mother. |
| George | Lawson-Young | A professor of respiratory medicine. |
| Gerard | Logan | Martin's friend. Narrator. |
| George | Newnes | The man who built the mansion on Hollerday Hill. |
| Norman | Osprey | A bookmaker. Rose's companion. |
| Eddie | Payne | Martin's racehorse valet. AKA: Ed. |
| Tom | Pigeon | The man who rescued Gerard. Aka: The Backlash. |
| Arthur | Robins | A bookmaker. Rose's grandfather. |
| Rose | Robins | Eddie's daughter. Victor's aunt. |
| Uncle | Ron | Gerard's uncle. |
| A | Spokesman | The informant on Dr. Force. |
| Leicester | Steward | The Steward of Cheltenham. |
| Bon-Bon | Stukely | Martin's rich wife. |
| Daniel | Stukely | Martin and Bon Bon's eldest son. |
| Martin | Stukely | Gerard's friend. Deceased. |
| Kenneth | Trubshaw | The trophy chairman. |
| Gina | Verity | Vic's mother. |
| Victor | Verity | Ed Payne's grandson. |
| Jim | | Gerard's driver. |
| Shepherd | | The police superintendent. |
| Tallahassee | | The steeplechaser. |
| Worthington | | Bon-Bon's chauffeur. |
