I thought of old Tom, kind sweet Tom, a gentleman who saw my need and matched it to his own; and Clive, the arrogant kid, assured beyond his age and possessed of a deadly determination to get his own way; and Mary, the Martha Stewart of the street, so curious but too uptight to enquire. I thought of Louis, my most recent conquest, and the thrill which went through me as I started to dominate him. I thought of the faceless and voiceless, the casual fucks and impromptu blowjobs, the little tests my Master had set for his slave girl. And every one, every single one, I had passed to his satisfaction.

Except one.

Sue.

Sue was my nightmare - literally so; I would wake in the night, sweating and tossing, Sue on my mind, her spiteful face filling my thoughts, the contemptuous look in her eyes, the acrid sound of her voice grating on my confidence. My Master considered her to be my next and biggest challenge but I was intimidated by her to a degree it is hard to describe: the mere recollection of the woman made my heart pound, causing an almost physical jolt to resound round my body; sweat would form on my brow and acid in my mouth and a feeling of dejection would overwhelm me. It was quite simple: I was scared of the woman.

And yet.

My Master, appalled by the casual violence of Sue's demeanour, had concocted a plan to entrap her and make her mine. It worked perfectly, with me the unwitting bait and Sue falling for it in as compromising a manner as it is possible to imagine. Left in the position where her infidelity to a jealous husband could be amply demonstrated, and what's more infidelity with another woman as well as a man, she was left in no doubt that compliance was her only option. And that meant compliance to me.

My Master's latest test for me, his biggest and worst, was to see Harriet the Slave Girl assume dominance over the woman who had so tormented and abused her. And I didn't think I was up to the challenge.

It had weighed on my mind for some weeks, and I knew my Master was agitating for action, but I simply didn't know what to do, how to instigate the affair. I had little confidence that I could control the woman and had no idea what to do if she refused my instructions. My Master, a gnomic smile on his face, refused to offer assistance.

"She will obey you," was all he would say. I wished I could share his confidence.

Finally, my Master lost patience and started proceedings himself by inviting Sue round one afternoon. I say "invited" although I overheard the telephone conversation and there was no element of freewill in it. "Harriet wishes to inspect you at 1.30 tomorrow afternoon, in her living room. Be there." That was it. How on earth was I to live up to that? I was a slave girl, a submissive who craved the decision of others to counter the indecision of myself. What was I to do?

I opened the door to Sue at precisely 1.29 the following afternoon. As our eyes met it is difficult to say which of us was the more uncertain in our unaccustomed roles. Her mouth and face was a featureless blank - deliberately so - except for the eyes, the malevolence of which she couldn't mask: they blazed in defiance, a rich blue hostility which ripped my fragile self-esteem asunder with one, baleful look. I couldn't control this woman.

"Come through," I said, my voice cracking. If only my Master were here. She followed and we stood, awkwardly, in the living room. What the hell was I supposed to do?

"Make me some coffee," I said and turned away. It was a gesture I hoped she would read as dismissive, although in truth it was because I was too scared to watch for fear of her refusing. I sat in my seat and looked up apprehensively. She was gone. A surge of relief swept through me as I heard her in the kitchen, gracelessly rattling cups and filling the kettle. She returned a few minutes later with a tray and two cups of coffee.

"I said make me coffee," I said coldly. "I didn't say anything about you." I think this surprised me as much as it did her. The words fell out of my mouth before I had even thought about them. "Take that back to the kitchen, pour it down the sink, clean the cup and return." Again, I felt I had little ownership of my words; rather, they tumbled out of me in an automatic response. It was almost as if I were projecting my Master into this situation and predicting how he would react. I relaxed slightly, feeling at last that my Master was, indeed, watching over me and giving his support. It was an important moment.

Sue returned, her expression still exuding defiance but also, it seemed to me, somewhat chastened. She stood before me, a gesture which seemed somehow unnatural. And then it hit me: my god, she was standing and waiting for my instruction. She was playing the game. She was obeying her Mistress. Now Sue was an intelligent woman, and an extremely egotistical one, and she wouldn't be acceding to this for the fun of it: I could only imagine that she had weighed the options and considered humouring my Master and me to be the lesser of two evils, the easiest path to follow. Let them have their fun, she must have thought, and life can return to normal. Even so, her natural arrogance would make this an excruciating submission. I can't begin to relate how it felt, that instant when I believed, only a part of me - but a significant part - that I could pull this off. Sue stood before me and I let her wait, deliberately sipping my coffee for some moments, watching her discomfort increase.

"What's past is past," I said at length. "And providing you obey me properly we need never revisit those events. But believe me, if you provoke me there is a whole lot you have to atone for. I could beat you from now till next Thursday for the things you've done to me. Just remember that."

Sue swayed uncomfortably. I could tell she was ready to bite and was trying hard to control her naturally aggressive instincts. I piled on the pressure.

"However, one thing which sticks in my mind is the very first time. It was humiliating beyond words. Do you remember what you made me do?"

Sue shook her head.

"I think you do. Try. In your kitchen. What was it?"

She bit her lip and stared at the carpet. Only now, I think, as the game began, did she realise what she had allowed herself to be drawn into. I could see her mind reflecting, remembering the things she had made me do, and I relished the pain in her eyes as she projected herself into those situations. "I made you strip," she said.

"Yes, you did. Now strip for me."