It was exciting when it started, then comfortable and domestic, and over time we grew apart. If it had been real, our relationship wouldn't have made a chapter in a memoir. But Mark was a fictional character, contrived by the British state to violate me and undermine the values I hold dearest. And the entire time, EN31 was sitting around the corner, writing it all down, watching our lives unfold.

In 2003, British police infiltrated a group of idealistic young environmental groups, forming sexual relationships and spying without warrant on hundreds of innocent civilians. Kate Wilson fought back. She took the Met to court, at times battling alone without funding or legal representation, enduring bullying, psychological intrusion and further state surveillance. It took her nearly 20 years to uncover the eerie truth about Britain's secret political police. This is her story.