In 1856 the Lunacy Commissioners announced that an asylum capable of accommodating 600 criminal lunatics was to be built in the Berkshire countryside, and that Sir Joshua Jebb, the architect of Pentonville and Holloway prisons, was to build it: thus was Broadmoor born. Ninety-nine years later my father was appointed its tenth medical superintendent.

When I went to the hospital as a boy, to see my father, I would be met by a male nurse in a black uniform with a peaked cap and a bunch of large keys attached to his trouser pocket. He led me through a double-locked door, along a flagstoned corridor, through a barred gate and down a cloister. We then crossed a courtyard, and, after a second double-locked door, entered my father’s office. A huge room this, with a huge desk, and beside the desk windows with a view over broad terraces and sports fields sweeping down to the perimeter wall. Beyond the wall there was farmland, gradually giving way to the wooded hills of Hampshire. What I remember most vividly about this room is a watercolour of a Victorian seaman. He is bent slightly at the waist, lifting his hat with one hand and clutching a fiddle and bow with the other. His left leg also is lifted, only there is no left leg; sticking out of his bell-bottoms is a wooden stump.

‘Sailor’ was painted by Richard Dadd, the Victorian artist who stabbed his father to death in Chobham in 1843, apparently believing him to be the devil, and then fled to France on a mission to kill the Pope. He was captured after attempting to cut a man’s throat in a coach and was eventually confined to the dark, cramped criminal wing of Bethlem Hospital, where he remained for twenty years until being transferred to Broadmoor. There, in tranquil, spacious surroundings, he resumed his painting, controlled, so he thought, by the Egyptian god Osiris. He died of consumption in the hospital in 1886, and is buried not far from the house I grew up in.