Sarah was raised in Hampshire, in southern England, with a younger brother. Her mother was a seamstress and her father a structural engineer. While growing up her ambition was to become a dentist. She refused to let anybody take photographs of her as a child because she was shy and introverted.

Sarah was 10 when her breasts began to develop and, at school, was teased mercilessly about it. This caused her to become embarrassed about her body and she took to wearing big jumpers and loose clothing to hide her rapidly developing figure.

It was while she was on a family holiday in Yugoslavia that she had her first sexual experience; the boy was a 22-year-old local and Sarah was 13. She did not find the experience particularly enjoyable. It was not until about a year later that she became truly sexually active with the realisation that she especially enjoyed having sex—preferably with a stranger—in public places: the prospect of being caught simply adding to the excitement; and caught she was on numerous occasions. On one such, the police found her having sex in front of the police station: they let her off with a warning. On another, the ticket collector of the train she was travelling on interrupted her and her partner having sex in one of the compartments. After seeing what they were doing he simply checked their tickets and left.