Lead Actor Nicholas Briggs said: "This is an entirely new approach for our Sherlock Holmes range. 30-minute, weekly episodes with exciting cliffhangers, and an audio style which is part traditional Holmes and part 1930s movie serial, with Jamie Robertson delivering a music score steeped in melodrama.

"What we have here are eight different episodes of Sherlock Holmes, all part of the same story, but they all have distinct little plots as well. It all fits together, and there are many clues to pick up along the way.

"What’s so lovely is that we’re doing this serialised version to recapture the spirit of the old Strand Magazine stories, and also to make a bit of noise about Sherlock Holmes and experiment with what it’s like to do a series released on a weekly basis."

Writer Jonathan Barnes added: "I was thrilled to be asked to return to the world of Sherlock Holmes for this very special release. It's my hope that Sherlock Holmes Untold provides plenty for fans to get their teeth into while also serving as the ideal jumping-on point for new listeners. It's the fastest-moving, most complex piece of storytelling that this range has ever done. Briggs and Earl have never been better and the guest cast is superb. There's something for everyone here!

"Fans of the Sherlock Holmes stories will know that Conan Doyle absolutely sprinkles them with all of these little mentions of unchronicled cases. Sometimes stories that were incomplete or unsatisfying, sometimes stories too scandalous to be told. This whole series is about building and extrapolating from the hints that Doyle left behind, almost like breadcrumbs for us to follow.

"This first two-part story comes from a reference in Doyle's The Problem of Thor Bridge to the well-known journalist and duellist Isadora Persano, who was found stark staring mad, staring at a worm in a matchbox that is unknown to medical science.

Director and script editor Ken Bentley said: "Releasing weekly episodes has given us the chance to try something new. I grew up watching the Flash Gordon serials with Larry 'Buster' Crabbe - it's a style of episodic storytelling familiar to anyone with an enduring love of cult film and TV, and it's the perfect way to tell the Untold stories. Jamie Robertson's sound design and score are among the best I've heard. The serial format seems simple, but it’s been some of the most forensic post-production I’ve worked on, and I can’t wait for listeners to hear it."