Despite Coward's lack of input to the film, Brunel undoubtedly felt his spectre hovering over the production of The Vortex. However, the very solid presence of two writers exerted a much more potent influence over his next film. Margaret Kennedy's The Constant Nymph was the bestselling novel of 1924 and had been adapted very successfully for the stage, so the news that it was to appear on screen was received with great anticipation. The Bioscope expressed the view of many in the business: ‘The purchase of the film rights of Margaret Kennedy's enormously successful novel and play by Gainsborough can be regarded as a triumph for British production and for Michael Balcon’ (3 March 1927: 30). Balcon was therefore under pressure to produce a film that lived up to the expectations of audiences and, with so much at stake, took on some of the pre-production work himself. Like The Vortex, The Constant Nymph dealt with a controversial subject, this time a love affair between a man and a young girl, though British censors were apparently appeased when they learned that Mabel Poulton, the actress playing the teenage lead, was actually in her twenties. A much more delicate negotiation for Balcon was with the authors of the play, Kennedy and Basil Dean (also director of the stage version), both powerful figures who had to be handled carefully if the production was to have a smooth passage to the screen.

Kennedy and Dean were newcomers to film but insisted on writing the scenario themselves; while their status as novice screenwriters may have given Balcon some concern, it was certainly beneficial to have their names attached to the project on a creative level. Although their screen treatment does not appear to have survived, Brunel's collection contains the Initial Continuity, which presumably stuck to it quite closely. This was written by Alma Reville, Alfred Hitchcock's wife, who had established herself as a talented screenwriter with an excellent eye for cinematic composition and a sympathy for narratives with strong female characters. Reville's draft was passed to Angus MacPhail to embellish and his scenario is also preserved in the Brunel collection. However, there are important differences between these and the finished film which illustrate that, once again, creative compromises were made.