Alfred Hitchcock only took on this version of Frederick Knott’s play to fulfil his Warner Brothers contract. Such was his lack of interest in the project that he claimed he could have phoned in his direction and that the action wouldn’t have been any less interesting if he had staged it in a phone box . . .
It’s true to say that many of the set pieces literally fall flat because they were originally composed for presentation in 3-D, but as playboy Tony Wendice (Ray Milland) plots to bump off his beautiful wife Margot (Grace Kelly) – who has been unfaithful with an American crime writer named Mark Halliday (Robert Cummings) – there are plenty of deft touches.
Tony wants the money in Margot’s will and blackmails his shady college acquaintance Charles Swann (Anthony Dawson) into performing the deed.
On the night of the planned murder, Tony has arranged the perfect alibi. He’s going to be with Margot’s lover, Mark, at a stag party, while Swann – using Margot’s front door key – sneaks into the apartment and strangles her with a stocking.
Tony telephones home at the very moment of Swann’s ambush (hence the “dial M” aspect of the title), and hears the vicious scuffle. But Swann bungles the attack, and Margot manages to stab her attacker in the back with a pair of scissors, and as he falls over he lands on his back – pushing the scissors deeper into his back.
Realising his plan has gone awry, Tony calmly adjusts to the situation on the fly and sets up Margot as Swann’s murderer. She is arrested by Chief Inspector Hubbard (John Williams) and goes to trial, where she is found guilty and sentenced to be executed.
The final scenes of the film balance Tony’s cunning mind against that of Inspector Hubbard while crime-writer Mark, desperate to save Margot from execution, begs Tony to confess to Swann’s murder, having concocted a crazy story about how and why Tony would have killed Swann (ironically – and with no inside knowledge – guessing almost the entire scenario correctly).
Chief Inspector Hubbard
Police Sergeant O’Brien