A lost Richard Dadd watercolour – a missing link in the artist’s enigmatic ‘Passions’ series – has re-emerged 136 years after it was last sold at Christies in 1870. Known simply by an abbreviated title: ‘Sketch to Ilustrate the Passions: Senility’, the image had never been reproduced and was unknown, visually at least, in the literature. In Dadd’s catalogue raisonee, it is listed as ‘whereabouts unknown’.

Dadd, a Victorian artist noted for his depictions of fairies and other supernatural subjects, was incarcerated in the Bethlem Hospital in 1843, after killing his father. It was in ‘Bedlam’ where Dadd produced his most celebrated works, including the powerful and mysterious ‘Passions’ series of genre pictures, each image depicting a vice, virtue or human characteristic.

The vast majority of these are now housed in National art collections and museums, but last week, at Bigwoods auctioneers in Stratford, the appearance in a general sale catalogue of an item described as ‘Possibly by Richard Dadd. A Sketch to Illustrate the Prisons (sic): Senility or Peevishners (Sic) Estimate £500-800’ caused a feeding frenzy in among the trade and other interested parties and was eventually knocked down for £31,000.

The successful bidder was Andrew Sim, who deals privately and through his father’s dealership, Michael Sim in Chislehurst, Kent.

Sim said: “I’m delighted. It is a thrilling discovery – I wasn’t able to sleep for excitement when I realised what it was - and a fascinating addition to Dadd scholarship. It is like finding one of the last missing pieces in a fabulous jigsaw puzzle. A completely fresh image by one of art’s great visionaries doesn’t turn up every day, let alone one of this quality.”

The Sketch consists of a sinister, weirdly postured figure dispensing what appears to be thin air from a box to a pair of ne-er do wells outside a tavern. Like many of the ‘Passions’, its meaning is mysteriously elusive.

Sim added: “It’s typically intriguing and quintessential Dadd: the extraordinary spider-like posture and menacing gaze of the central character are quite unforgettable.”

Of the 30 watercolours in the series, roughly half are still in the possession of the Bethlem Museum; the rest are held by the British Museum, the Victoria and Albert Museum and other major institutions.