Bow Street is often mentioned in Regency novels, some are even centered around the famous Runners of the time. Simply, a Bow Street Runner was a professional thief-taker who answered to the law enforcement office in Bow Street. They could be, and often were, hired by private citizens or organizations to recover or protect property or relatives. They were held in some awe by the general public.
The novelist Henry Fielding was appointed magistrate in 1749. His base of operations was in Bow Street and his inclinations as a social reformer eventually led to his forming the specialist thief-takers known as the Bow Street Runners. His brother worked with him and took over in 1754. The Runners were disbanded in 1839.