Link is a teenager born in Bradford in 1977 who adopts an alias to distance himself from his past. He becomes unhoused after his mother's aggressive new boyfriend forces him out of his childhood home. Vulnerable but observant, Link travels to London searching for work, only to find himself trapped in a cycle of poverty and invisibility. He is desperate for human connection and relies on his instincts to survive the freezing nights and dangerous streets.

Shelter is a 47-year-old former soldier recently discharged from the Army on medical grounds after 29 years of service. He holds a deep obsession with military discipline and immaculate cleanliness. Operating from a meticulously tidy ground-floor apartment, he uses politeness, fabricated stories, and a pet cat to appear harmless. He views the unhoused population as "garbage" dragging the country down and treats his violent mission as a military operation.

Ginger is a streetwise young man who has been surviving on the streets of London for about six months. He knows the geography of the city's shelters, churches, and public washrooms, passing this critical knowledge to newcomers. He provides crucial companionship to Link, proving that trust and friendship can exist in an otherwise cold environment.

Introduced as an unhoused young woman from Glasgow, Gail possesses striking features, chestnut hair, and dark eyes. She quickly forms a close attachment to Link, learning how to beg for change while keeping him company on the streets. Her presence gives Link a renewed sense of hope, though her frequent use of phone booths and unusually specific questions about street life occasionally make him suspect she is hiding something.

Vince is a man in his fifties who dates Link's mother. He enjoys drinking, dresses to look younger than his age, and creates a hostile environment in the household. He views Link as a burden, mocks him for being unemployed, and eventually locks the teenager out of the house entirely.

Carole is Link's older sister by four years. She tries to support him when their home life deteriorates and occasionally offers him a place to stay after she moves out. Her ability to help is severely restricted by her boyfriend's intolerance of Link.

The mother of Link and Carole. Before Vince arrived, she provided a stable, predictable home. She becomes entirely submissive to Vince's demands, failing to intervene or defend Link when Vince locks him out of the house.

An unhoused young woman (whose real name is Tanya) who associates with Ginger. She later goes missing from the streets under suspicious circumstances, prompting a search.

A middle-aged man actively searching the streets of London for his missing daughter, Tanya (known as Toya on the streets). His investigation provides crucial clues about the last known whereabouts of the missing individuals.

A 35-year-old man whose real name is Probyn. He wears Wellington boots and a waxed jacket, and keeps a Rottweiler. He operates "floating dosshouses," consisting of six converted boats where unhoused people can sleep on the floor for three pounds a night.

A local paper seller who observes the daily movements around the station. He proves to be an important source of information regarding the men and women passing through the area.

Carole's boyfriend. He strongly resents Link crashing at their home and views the teenager as a burden, eventually making it impossible for Carole to continue offering Link shelter.

A cat acquired by Shelter specifically to project an image of harmless domesticity. Shelter hates cats, but relies on Sappho to lower the defenses of the people he invites inside.