Authorship of The String of Pearls (Sweeney Todd) was long attributed to Prest. This was successfully challenged in 2002 by Helen Smith. Her certainty that Rymer was the author is based on Lloyd‘s business records and backed by textual analysis.
Lloyd published what is treated as the definitive version in The People‘s Periodical in 1846-47. This is judged to be superior to the longer single-volume version published in 1850.
The story itself was not original. According to Peeps into the Past, it was first written in the French "Fouché‘s Archives of the Police", then written by Prest in English under the title "A Terrific Story of the Rue de la Harpe, Paris". This was published in 1824 in Mary Elliott‘s The Tell Tale. She was a prolific author who wrote children‘s literature — the genre to which, chillingly enough, this terrifying story was assumed to belong. If this is the case, Prest would have been 14 at the time.
According to the same source, Lloyd published Sweeney Todd first in 1840, written by Prest. However, it describes this as “a very rare item, and seldom met with” (in 1919). We have not found it referred to elsewhere.
Helen Smith points out that The Tell Tale was re-issued in 1841. She also notes Lloyd‘s publication of a very short story, Joddrel the Barber; or, Mystery Unravelled in Lloyd‘s Penny Atlas (Vol 2, No 97, 1844), as a possible development - it has a similar plot but no pies.
Some confusion has been created by the date given for the play written by George Dibdin Pitt and said to have been “first performed at the Britannia Theatre, 1842” on the title page of the version printed by John Dicks. Dicks‘ Standard Plays (undated) attributed the play to “Pitt (Prest)”. Since other evidence indicates that it was first performed in 1847, the misleading date given in the printed version may simply have been a typo.
Robert L Mack explores the controversy of authorship in detail in The Wonderful and Surprising History of Sweeney Todd: The Life and Times of an Urban Legend (2008). Regardless of authorship, the story of Sweeney Todd has had a long life. It has appeared in play, ballet, film and musical form countless times. The 1979 Sondheim-Wheeler musical ran intermittently in the West End for 22 years. It was revived for a short run in semi-operatic form at the London Coliseum in March 2015.