She appeared in the 1992 film adaptation of Graham Swift's novel Waterland, alongside her husband Irons.
Cusack and her son, revealed to be the Irish Trotskyist politician Richard Boyd Barrett, have since been reunited.
Article cannot be re-published in any other pages or documents.
In 1970, she starred with Peter Sellers in the film Hoffman.
The main character is portrayed by Mark Williams, while Sorcha plays Mrs.