Cast a Dark Shadow is a 1955 British suspense film noir directed by Lewis Gilbert and written by John Cresswell, based on the 1952 play Murder Mistaken by Janet Green.

[2] It stars Dirk Bogarde, Margaret Lockwood, Kay Walsh, Kathleen Harrison and Robert Flemyng.

Married for a year, Edward "Teddy" Bare kills his wealthy older wife Monica after she asks her lawyer Phillip Mortimer to change her will.

He stages it to look as if she accidentally asphyxiated while drunkenly trying to light the gas fire (he having assiduously encouraged her to drink heavily as part of his control over her).

To his chagrin, he discovers that she intended to leave him all her money; instead, he only inherits the mansion from a previous will while her fortune is left in trust to her only relative, her sister Dora.

As Edward was an estate agent before he married Monica, he shows her several properties, making Freda jealous.

[8] However Dirk Bogarde said "the film was a failure": It was the first time I had come under another star's name – Margaret Lockwood – and it just died, which was a pity because it was a very good movie and I had persuaded Maggie to do it.

Monthly Film Bulletin wrote "This is an old-fashioned and thorough-going melodrama, adapted from the stage and retaining – notably in the big scene in which Bare confronts his victim’s sister – a decidedly theatrical flavour.

It is conventionally but quite competently managed, achieving an occasional note of the authentically squalid and shabby in developing Bare’s dealings with the three women.

Margaret Lockwood’s performance as the retired barmaid, although built up largely through mannerisms, has considerable spirit.

"[10] Bosley Crowther of The New York Times wrote that the actors are skilled but "they are not offered many opportunities to make Cast a Dark Shadow mysterious or tense.

"[14] Leslie Halliwell stated "Unambitious but enjoyable melodrama, well acted though with directorial opportunities missed.