In Girl Without a Voice, Leah Goulden attempts to join The Living Saints, an exclusive Christian cult. Creating a fictional cult is relatively straightforward for a novelist because there are so many harrowing survival testimonies to borrow from. My Living Saints see themselves as above the law. Led by God's Man they are a narrow, utterly male dominated sect. These men maintain power through the two witness rule: the elders will not investigate a complaint that only has one witness to it, so abuse is sanctioned. My cult sees the world as evil. Its members mustn't eat or drink with outsiders. Any deviation is punished by being cast out, a process that splits marriages.

Leah has to join because her mother has been sucked back to the group that destroyed her as a young girl. I make my character walk open-eyed into this warped world which bans computers and mobile phones. She does this willingly, putting herself back in the power of a man who raped her.

Such cults are clear perversions, but any small group can become a cult by keeping exclusively to one way of thinking, by never meeting the challenge of the opposite view. Indeed algorithms on social media create cults. A key figure in my cult tells Leah that everything is sanctioned somewhere in the Bible, if only you know where to look.