Recording in the sewer sets proved problematic, as imperfect waterproofing resulted in severe leaking through the studio floor onto The BBC switchboard. These sequences were also difficult for Louise Jameson, who was suffering from glandular fever. Not only did she have to contend with thrashing about in the water, but she discovered that the undergarments which made up her costume became partly transparent when damp.
This episode takes place in London in 1889.
This episode was watched by 10.2 million viewers on its original transmission.