When Celia and Maria argue beside the park, they are stood outside the former home of Joseph Bruce Ismay. Ismay was the managing director of the White Star Line and survived the sinking of the company's most infamous liner, The Titanic.
Mattia Paradiso and Michael Dolan who play father and son, Giovanni and Tomas (Tommy) Cipriani, previously worked together portraying soldiers in the war drama Tolkien.
Enemy of the Heart is inspired by true events surrounding the ill-fated voyage of the S.S. Arandora Star transporting UK-based Italian, German and Austrian internees from Liverpool, England to Newfoundland, Canada during World War Two. Those aboard were considered 'Enemy Aliens' when Italy and Germany joined forces to attack France and Britain.
One of the principal characters is named after the writer's Great grandmother, Irish-born Maisie O'Connor. Her wedding photograph taken in 1925, features in the O'Connor and Cipriani homes. Maisie born 1904, died at the age of 104 in Liverpool, July, 2008.
More than six hundred actors applied for principal roles in Enemy of the Heart. Every application, regardless of experience, was considered with actors auditioning over the course of two months via showreels, Zoom and self-tapes.