In early 18th century London, the victim of a robbery could do little more than shout stop thief and hope a neighbor gave chase. The British feared a state police force as a tool of tyranny, so the government offered cash rewards instead and got a trade in extortion. Thief takers such as Jonathan Wild staged robberies, returned the goods for a fee, and sent their own men to the gallows for the bounty. This episode follows the two brothers who built something better from inside that broken system.

Henry Fielding, the author of Tom Jones, became a magistrate in 1748 and worked from his house at number four Bow Street. He gathered six trusted men, armed them with special warrants, held hearings in the open, and won a government budget of 200 pounds a year so they could be paid a wage. When he died in 1754, his blind brother Sir John Fielding took over and turned a courtroom into a national intelligence network of clerks, newspapers, and roadside informants.

• Rewards of 40 pounds, later 100, for catching a highwayman were meant to help victims and instead created a freelance bounty industry.
• Known as the blind beak of Bow Street, John Fielding was said to recognize thousands of repeat offenders by voice alone.
• John raised the budget to 400 pounds in 1757 and 600 by 1765, funding horse patrols against highwaymen.
• Turnpike gatekeepers and publicans fed him reports by mail coach, and descriptions of suspects ran in the Public Advertiser.
• In 1802 the runners arrested Colonel Edward Despard over a plot to assassinate the king. They were disbanded in 1839, after the Metropolitan Police Act of 1829.