In 1998, the Science Museum marked the 750th anniversary of Bethlem Hospital with an exhibition entitled “Surprising Regions of the Mind”. It featured works by the fairy painter Richard Dadd, the cat painter Louis Wain, the Royal Academician Charles Sims and the dancer Nijinsky. The common denominator was that they were all produced while their makers were inmates of the psychiatric institution known as Bedlam.The most notorious of the group was Richard Dadd (1817-86). Unlike the others, who had merely suffered mental breakdowns, Dadd had acted on his delusions and murdered his father. Following “secret admonishings” that Dadd senior was a demonic impostor – his real parent being the Egyptian god Osiris – Dadd had lured his father into Cobham Park in Ke