Hilary Wentworth features prominently across the St. Clare's book series, first appearing in *The Twins at St. Clare's* and remaining through *The Sixth Form at St. Clare's*, where she departs after one term to join her parents in India.

Initially described as a cheeky-looking girl with blonde hair, later books depict her inconsistently with dark hair. She holds head girl positions in multiple forms, embodying responsibility and approachability as a reasonable authority figure who mediates conflicts and upholds fairness.

Her principled nature emerges in *Fifth Formers of St. Clare's* when she confronts Angela Favorleigh over Angela's exploitative treatment of younger students performing fagging duties. Hilary further demonstrates commitment to justice by rallying peers to advocate for scholarship opportunities for Lucy Oriell, whose education faces financial hardship.

Her background includes staying at St. Clare's during holidays while her parents were in India, paralleling Gladys Hillman's circumstances. Her departure becomes permanent upon her family's relocation to India.