Isabel O'Sullivan

Isabel O'Sullivan is a student at St Clare's School. She is one of the main protagonists of the series and appears in all nine books

Personality and Appearance
Isabel is described as having dark brown wavy hair, deep blue eyes and a merry smile, with an Irish lilt to her voice that is very pleasant to hear.

Isabel is generous and friendly. She has a calmer temperament and often tries to keep her more hot-headed twin from losing her temper.

Backstory
Isabel was born along with her twin Pat in summer 1927, around the same time as her cousin Alison.

Isabel was a head girl of Redroofs School along with Pat. She attended alongside her cousin Alison and was friends with Mary and Frances Waters. She was also tennis captain and won a championship.

The Twins at St Clare's
Isabel follows Pat's lead at St Clare's, doing as Pat says despite not always agreeing. She is disgusted by the fact that St Clare's plays lacrosse instead of hockey. When they arrive, none of the girls talks to them as they look 'stuck up'. They also get off on the wrong foot with Janet Robins. Isabel and Pat are the despair of some of the teachers, especially Mam'zelle. However, Pat argues back, whilst Isabel is embarrassed. When Belinda Towers asks the twins to do her jobs, Pat refuses. Isabel is upset and wants to do as Belinda says, but Pat is angry and after a failed attempt to involve the head girl Winifred James, Pat flounces off and Isabel gets Kathleen Gregory to help her. Belinda bans Pat from going to town, but Pat goes anyway, pretending to be Isabel, so when Belinda sends for Pat, Isabel has to pretend to be her. Belinda has written Pat down to be in a lacrosse match, but when Isabel tells her, she feels mean because of the trick she played on Belinda. Pat confesses and Belinda lets her play anyway, with Isabel cheering her on. Mam'zelle is angered by the twin's work, and Isabel is almost reduced to tears by her scoldings. She insists they redo their essays, but Pat protests that they are going to the cinema. Isabel is forced to go along with Pat to the cinema after teatime and they sneak out of bed and do their essays late at night, in order to hand them to Mam'zelle. They run into Miss Theobald, who straightens the problem out by Mam'zelle giving them extra coaching. Janet is sent fire-cracks by her brother, and she throws them into the fire during Miss Kennedy's class, but she throws in too many and the fire becomes dangerous. Miss Roberts is furious and orders the person behind the prank to own up. Isabel goes along with the rest of the form to own up and take the blame. Isabel loses a pound of money, so has to borrow from Pat to put towards Miss Theobald's birthday present. Janet's birthday comes up and the first form decides to have a midnight feast. Isabel borrows from Pat to buy a bar of chocolate. Miss Kennedy catches them in the act but decides not to report them, earning the girls' gratitude. Isabel, Doris Elward and Vera Johns feel ill the next morning. Isabel and Kathleen are chosen to play in a lacrosse match that week, and Hilary Wentworth reminds Isabel teasingly of her views on lacrosse at the beginning of the term. Isabel shoots the winning goal of the match. A few other people's money goes missing, and the twins discover the culprit to be Kathleen, when Rita George, a sixth former, catches her and goes to the head. Pat and Isabel race in afterwards, and explain Kathleen's side of the story. Kathleen is permitted to stay. The first form better behaves in Miss Kennedy's class afterwards, but the second form wasn't. The two forms scare Miss Kennedy with a cat, but Kathleen and the twins overhear Miss Kennedy telling her friend Miss Roper about the girls, and about her sick mother and money troubles. The girls are horrified and write an apology note to Miss Kennedy, promising to work harder in future. The circus comes to town, but the first form is forbidden to go after their classroom window is broken. Pat, Isabel, Janet and Kathleen play truant and sneak out to see the show, but later the class is taken to the circus. The four girls debate going but come down with colds after their night out. A row blows up with Janet and Sheila Naylor, so the twins help her get back on track. Exam season arrives, and the twins cram for geography, but when Isabel goes to get a knitting pattern book from her desk, she sees the questions for the test on Miss Roberts' desk and reads them. Pat tells her to do badly in the exam, so when Miss Roberts scolds her, she can explain. However, at the last minute, it is revealed that they are the second form papers, so Isabel is able to start a clean slate, but the experience shook her and she made silly mistakes, ending up in sixth place.

Trivia

 * The name 'Isabel' is of Spanish origin meaning 'pledged to God'.