I had been obsessed with spies since I was a very little girl. My grandmother told me that my father used to play ‘I Spy’ with me, using the game to show me the world. I liked to imagine him in his blue-grey RAF uniform, pointing into the night, where he would soon be flying.

I Spy with my little eye, something far up in the sky . . .

. . . Moon.

When I was five, I tiptoed into the sitting room and hid behind my grandmother’s brown-velvet wingback chair to peek at a film she was watching. I sat, cross-legged, on her scratchy brown carpet, so perfectly still and quiet she never knew I was there. To this day I don’t know what the film was called. Only that it was about a spy who pretended to his family he was a boring businessman. Then, a bad spy injected him with truth serum, and this made him confess to his wife about his double life as an intelligence officer.

With the reasoning of a five-year-old, I decided to make my own truth serum and administer it to my grandmother, using the best available laboratory facilities. While she was cooking dinner, I sneaked into her bedroom and scooped out tiny spoonfuls of the lotions and scents on her dressing table, then stirred them into the moisturising cream she rubbed onto her face each night. My fantasy was that the serum would force my grandmother into revealing the secrets I was certain she was keeping about my parents.

When I was ready to begin the interrogation, I noticed that she had a bright-red and extremely bumpy rash on her cheeks. She never imagined the cause, and I crept back into her room to steal the cream away and dispose of it at the bottom of the kitchen rubbish so she would never use it again. I was frightened that I’d mortally injured her, but she seemed to recover quickly.

On my eighth birthday, Harriet the Spy appeared in my Christmas stocking, and Harriet became my absolute hero. She carried her spy notebook everywhere, so I did too, writing little observations about everything I saw. I made things up as well. It was only later that I learned that spies were supposed to keep to what was true, and were trained to be cautious about what they put on paper – two principles I wasn’t very good at heeding.

‘I can see that you have been commendably strategic and goal-driven in wanting to join us.’ Maxine gave me another of those intimate nods. ‘But in this line of work, how far would you push it? You’re very attractive.’ Despite the appeasing gestures, Maxine shifted the subject with the suddenness of a window exploding in a storm. ‘You know that.’

I blinked at this new Maxine. She was being kind but firm, friendly but still clearly the one with the power.

She pushed at me again. ‘Where does the line come, Holly?’