Lingard wrote other books about adolescents struggling to deal with the conflicts in Northern Ireland during World War II. The Twelfth Day of July begins Lingard's Kevin and Sadie series, which is set in Ulster and deals with the religious conflicts between Catholics and Protestants. Across the Barricades, the second book in this series, won an award for its poignant depiction of Kevin and Sadie's struggle to find fulfillment in a city stifled by religious and social prejudice.