‘Okay,’ I say, ‘lift your leg up’, and she obliges, familiar with our well-practised routine. I remove a key from my pocket and undo the padlock attached to the clamp around her ankle. The chain falls to the floor with a heavy thump. I attach a second, much shorter clasp and chain to her ankle and lock it. This chain doesn’t extend far from the spike. Once again, I have her confined to her bedroom.