Tom is a naive 17-year-old laborer who repairs gutters across London. Inexperienced in romance and newly exposed to the workforce, he possesses an active imagination that quickly romanticizes his surroundings. He operates a step removed from his older coworkers, preferring to construct internal, chivalric fantasies rather than share their blunt hostility.

Stanley is a sharp-faced, 20-something newlywed who works as a manual laborer. He is quick at his job and generally good company under normal weather, but the severe heat wave triggers his volatile temper. His traditional views on marriage make him highly reactive to women who display independence or ignore his authority.

At 45, Harry is the oldest and most practical member of the three-man work crew. He takes charge of the labor conditions, borrowing blankets to create shade and deciding when it is time to halt work for the day. Though he initially presents himself as the voice of reason, his patience wears thin under the grueling heat and perceived dismissals from those outside his social class.

The Woman is a nameless London resident who uses her high-rise rooftop to sunbathe during a rare period of extreme weather. She seeks only to tan and relax in privacy, responding to the workmen's whistles and shouts with calculated silence. Her refusal to acknowledge the men or conform to their expectations drives the primary conflict on the rooftop.

Mrs. Pritchett is a smart, blonde housewife around 30 years old who is married to an airline pilot. She occupies a higher social class than the laborers but welcomes them into her kitchen to provide refreshments. She adheres to traditional gender norms, making the men comfortable with her friendly and conventional demeanor.