Camberwell child poisoner

The Camberwell child poisoner was a murderer who poisoned children in 1890s London. The Paternoster Gang investigated the case, and Madame Vastra had him over for interrogation and dinner. The morning of their interrogation, Vastra's wife Jenny Flint warned Clara Oswald, who stayed with them at 13 Paternoster Row shortly after the Eleventh Doctor regenerated into his twelfth incarnation, to avoid the larder later on account of the noise. (TV: Deep Breath)