This is a rather oddly presented story with the common theme of something awry with the nanny....or butler or....anyone who you think you can trust.
Suspense films like this are excellent in that one really can guess what is to happen next, and the characters and their behavior is quite mercurial.
Wendy Craig , (who later starred in comedies such as "Butterflies" on NY station PBS) is good here as the mother of young Joey Fane, a troubled child with whom no one seems to know what to do with. Or is that really the case?. There is a Hitchcockian element to this story in that the black and white cinematography is slightly foreboding, little Joey's butter cream cake (to welcome him home after the hospital) looks inviting, but is it poison?.
Jill Bennett who has been in other films of this genre as the narcissistic aunt Virgie, who feels she is up to the task of minding Joey until odd occurrences begin to shake her resolve.
Ms. Davis as the nanny has a secret past, which is not divulged other than when we see the squalor in which her own daughter had lived. Her expressions are sublime, then jaw dropping. She acts with expression, her movements and beats are the mark of her talent. She does not need to vocalize what is percolating internally. A gem here worth seeing for Davis alone. 9/10.