Cloudburst centres on cryptographer and a former Special Operations Executive agent John Graham (Robert Preston). When his wife (Elizabeth Sellars) is killed by a hit-and-run driver, Graham uses the skills he learned in the SOE during World War II to exact revenge.
Cloudburst was based on a play written by Leo Marks, today best known as the screenwriter of the classic Peeping Tom (1960). To a degree Cloudburst was inspired by Mr. Marks's own life. During World War II he worked as a cryptographer for the SOE on Baker Street in London. He would later write based on his experiences as a cryptographer, Between Silk and Cyanide: A Codemaker's Story 1941–1945 (published in 1998). It seems possible that even the hit-and-run death of John Graham's wife could have some basis in Leo Marks's life. During World War II he fell in love with a young woman named Ruth Hambro. Sadly, Miss Hambro would be killed in an airplane crash in 1943. While they were never formally in a romantic relationship (Mr. Marks was too shy to tell her how he felt), she served as the inspiration for one of his best known poems, "The Life That I Have." Beyond Ruth Hambro, Leo Marks also had female friends who were also fellow SOE agents who died during the war. Both Violette Szabo and Noor Inayat Khan, with whom Mr. Marks worked and was close, were killed by the Nazis. If John Graham's grief and rage in Cloudburst seems genuine, it seems possible that it is because Leo Marks had experienced them himself.
Cloudburst was Hammer's first real attempt to break into the American market. It was co-produced by Hammer Films' own Anthony Hinds and Hungarian American producer Alexander Paal. It was Alexander Paal who brought Robert Preston onto the project. Mr. Paal paid 75% of Mr. Preston's fee and even his living expenses while in London in return for 75% of the film's distribution rights in the Western Hemisphere. Originally Eagle-Lion Films was set to distribute Cloudburst in the United States, but the company ceased operations before the film's release. Cloudburst was then distributed by United Artists in the United States.
In many respects as the first American co-production Cloudburst marked as great a shift for Hammer Films as The Curse of Frankenstein six years later. Robert Preston would not be the last American leading man cast in a Hammer movie, as the studio would do so repeatedly in following years in an effort to attract American audiences. It was following the release of Cloudburst that Hammer Films would sign a four-year production and distribution with Robert Lippert of Lippert Pictures. Essentially, Lippert Pictures would distribute Hammer Films in the United States and Hammer Films would distribute Lippert Pictures in the United Kingdom. Such films as Stolen Face (1952), Wings of Danger (1952), and The Last Page would be released under this agreement.
Aside from being one of Hammer's earliest attempts to break into the American market, it was also historic as the first Hammer movie to be filmed at Bray Studios, where such classics as The Curse of Frankenstein, Dracula (1958), and The Mummy (1959) were filmed. Bray Studios was originally Down Place, a private residence built in the 1750s. The house was vacated in the 20th Century and eventually fell into disrepair. Hammer Films shot portions of their film The Dark Light at Down Place. In need of a studio, Hammer bought Down Place and remodelled it as a movie studio.
Cloudburst stands out among Hammer's pre-horror films. The film presents the grief and anger at the death of a loved one in a way that few movies had done before. This is aided by the performance of Robert Preston,whose John Graham is about as far from the congenial Harold Hill of The Music Man as one can get. John Graham is a man consumed by the grief over his wife and the anger at her needless death. In any other film Graham might have been presented as a villain, but in Cloudburst he comes off sympathetically, making it one of the earliest Hammer Films to do away with conventional morality. Indeed, Cloudburst is not light, popcorn fare. In their review of the film in the critic at Harrison's Reports wrote of the film, "Most picture-goers probably will find it too grim for enjoyment."
Cloudburst was a historic film for Hammer Films in many respects. It was their first American co-production and the first to be shot at Bray Studios. It set the pace for many Hammer movies to come, even once the studio shifted more towards the horror genre. Not particularly well known today, it deserves to be better known.