Sweeney Todd in the context of Mrs. Lovett

Penny dreadfuls were cheap popular serial literature produced during the 19th century in the United Kingdom. The pejorative term is roughly interchangeable with penny horrible, penny awful, and penny blood. The term typically referred to a story published in weekly parts of 8 to 16 pages, each costing one penny. The subject matter of these stories was typically sensational, focusing on the exploits of detectives, criminals, or supernatural entities. First published in the 1830s, penny dreadfuls featured characters such as Sweeney Todd, Dick Turpin, Varney the Vampire, and Spring-heeled Jack.

The BBC called penny dreadfuls "a 19th-century British publishing phenomenon". In America in the 1840s, a similar class of consumer content developed known as city mysteries. By the 1850s, there were up to a hundred publishers of penny-fiction, and in the 1860s and 1870s more than a million boys' periodicals were sold per week. The Guardian described penny dreadfuls as "Britain's first taste of mass-produced popular culture for the young", and "the Victorian equivalent of video games".