Cyril Tanner is the carriage driver of the London Institute.
Cyril worked at the Institute in Brighton, where he was trained fairly well to fight, while Thomas was in London, as a driver and a servant. When he was killed, Cyril moved to London to replace him.
He and Thomas shared some similarities but were also quite different. Cyril had a calmer and less diffident demeanor, whereas Thomas was more high-strung in comparison.
He is said to be handsome, like Thomas, but often wore a scowl that spoiled his good looks.