A portrait painted by an acclaimed Victorian artist while he was a long-term psychiatric patient is to return to the hospital where he spent 20 years, which is now a museum.

Richard Dadd was sent to Bethlem Royal hospital in south London, from which the derogatory term “bedlam” is derived, as a “criminal lunatic” after stabbing his father to death in 1843. He was later moved to Broadmoor, where he remained until his death in 1886.