Stephanie is the drug-addicted teenage girlfriend of Jeff Whittaker. She’s described as appearing emaciated with “dark, dirty hair … pulled back off a sunken, rabbity face, which had the violet-shadowed pallor of a consumptive.” She has extremely skinny legs and often is seen with “arms crossed tightly across her thin torso.”

By staking out Whittaker’s flat, which is located above a chip shop in Catford Broadway, Strike discovers that Stephanie is living there as well. He often sees her come downstairs to the chip shop to buy Cokes. Shanker had reported to Strike that Whittaker is Stephanie’s pimp, although when Robin has a conversation with the young girl, it is obvious that she is also “in love” with Whittaker.

When Strike gets involved in a physical altercation with his former stepfather, he offers to help Stephanie get away from Whittaker, who is physically abusing her. Stephanie refuses to leave his side.

In the TV series adaptation, Stephanie is portrayed by actress Ellie James.