Laffan blamed the Roman Catholic Church's ban on artificial birth control for his family's financial problems, saying: "I am a product of my father's belief in God rather than his belief in sex". His play "It's Two Foot Six Inches Above the Ground World" portrays an Irish Catholic family's family planning problems. Irving Wardle in the "Los Angeles Times" in 1970 called it "comedy that is clearly rooted in pain"; the "New York Times" in 2010 called it "potty-mouthed". It carried the warning: "It may not be for those who could find a frank discussion of sexual and religious matters not to their taste." It was a West End hit and was made into a film in 1972 as "It's a Two-Foot-Six-Inch-Above-the-Ground World", later retitled "The Love Ban". His 1994 play "The Missionary and Other Positions" is about sex. Other later plays include "Never So Good" (1976), in which a bomb-wielding terrorist visits a group of black squatters, and "Adam Redundant" (1989), which reverses the roles in the Garden of Eden by making Satan the hero.