Isobel Pickwell is the Deputy Headmistress at Abbey Grove. She is a very strict woman who believed in rigid discipline. Alfie often compares her to an SS Officer and makes fun of her fascist views. She was deeply conservative and religious, with contempt for what she believes are Rosie's attempts to turn the school into a "hippie commune": during her own sexual education class, she reads passages from the Bible to her students that forbid premarital sex. Her classroom and office are dark and bleak, with the only decorations being various pictures of dictatorial heads of state. She frequently schemes for more power, and nearly succeeds in unseating Fraser as Headmaster in the final episode of Series 1, until Jing proved that she had been stealing money from the school by lying about her expenses. Alfie and Rosie blackmail her into telling the board that Fraser is an excellent headmaster in exchange for them not exposing her. In the same episode, she reveals that she hasn't cried since 1990 – "when [Thatcher] was hounded out of office by her own party." In Series 2, upon learning of Rosie's lesbian relationship with Alex Scott, she secretly confesses to having previous lesbian relationships and attempted unsuccessfully to flirt with Rosie. Although in the Bad Education Handbook, she (correctly) predicts that Rosie's sexuality was a phase and that she would soon return to heterosexuality. In Funeral, she is believed to have died after committing suicide over the abuse received from Alfie's class, culminating in her being covered in glue whilst being distracted when answering a staged "phone a friend". In her suicide note, she directly blamed Alfie for her decision. However, she revealed to Alfie that she faked her death in order to escape debtors and to live with her penpal, "The Beast of Bergendorff", a German dentist in his nineties who lives in Argentina. In the same episode, her ringtone is revealed to be California Love. She returns in the final episode of Series 2 and buys Alfie at a man auction for £25,000, more than enough to save Abbey Grove. She reveals she became a millionaire after the German died and she inherited his fortune. It is not known what Pickwell does with Alfie after she won him in the man auction; but the only relating shot showed Pickwell riding on Alfie like a horse complete with saddle, while both were in their underwear. She is never mentioned and never appears again after that.

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