Ask around now and grown men will lower their voices about it. A children's film that colonized British nightmares.

He lives in a place called Rhododendron Mansion. He is six feet tall, dressed in a frock coat and top hat, and appears only if you close your eyes and perform a summoning ritual.

On paper this one is Harvey for kids, a gentle fantasy about an invisible rabbit and the girl who befriends him.

The costume, with its fixed stare and too-human bearing, lands somewhere between quaint and deeply wrong. Add a gamekeeper who threatens little Mary with a shotgun and you get a film that ran on Easter and Christmas television to haplessly unnerve a generation.

MR. HORATIO KNIBBLES (1971) came from the Children's Film Foundation, the publicly funded outfit that turned out wholesome hour-long pictures for Saturday matinees.

Those who grew up with Mr. Knibbles still carry the scars.