The setting of The Chocolate War is characterized by both place and time. The Vietnam War provides a temporal (time-oriented) backdrop for the novel and an all boys public school, Trinity, provides the physical setting.
Each of these elements of the setting are significant to the story and characters of The Chocolate War.
Early in the novel, the idea of conformity comes up when Jerry is confronted by one of the "hippies" from the park across the street from the school.
Jerry is mocked by their spokesman as a "square," as someone hidebound by his smart uniform, his obedience to rules, and his sense of guilt...
This counter-culture social dynamic of the Vietnam era helps to establish the theme of Jerry's later dilemma in the novel - to conform or to resist conformity.
The park where the "hippies" spend their time is across the street from the school, close enough to see but separated from the school. On one side of the street the "hippies" refuse to conform and to be "squares".
On the other side of the street is Trinity, an institution defined by conformity, where students wear uniforms, suffer the pressures of the Vigils, and are expected to fall in line with faculty desires.
The major themes of the novel are implicit in the contrast between the non-conformist "hippies" and the atmosphere of conformity in the school.