So we understood each other. I took my wallet from my back pocket. The demeanour of my robbers – I knew, now – had changed. We were into the delicate, unambiguous business of separating me from my possessions by threat of force, we all knew, and they had lost their stony composure and focus and become watchful and jumpy, eyes everywhere, lots of small movements. Railing took my wallet from me as soon as it appeared.

‘Phone,’ Old-Young said, beckoning impatiently. This was the least ambivalent instruction he gave me. I took my phone from my jacket pocket and Railing took it from me. This teamwork was notable: one doing the demanding, the other the taking. Did this offer some consoling moral effect, or imagined legal protection?

It didn’t matter, and my thoughts were cancelled when Railing hit me. I had no time to prepare. Even consumed by fear of imminent attack, I had not expected it. (So what was the fear for? What good was it?) There was a fraction of a second in which I realised ‘he’s going to hit me’ – his frame coiling back, eyes widening – then a flash of action and pain.

The punch wasn’t tidy. You only learn this after you’ve been hit a couple of times by people who mean it, but punches are messy, slippery affairs. Think ‘punch’ and, for me anyway, what came to mind was Raging Bull: slow-motion black and white arm-back bull’s-eye connection. Not a smeared moment of edges and glancing and sliding and mismatching body parts.

He hit me below the right eye, mostly on the cheekbone. It felt as if he were aiming elsewhere and missed, but that was mad, at that range surely he could hit wherever he wanted. I cried out and raised my arms to protect my face. Too late, of course, everything that happened had already happened, they were gone, off round the corner the quickest you can walk without running, all hands now in jacket pockets.

My first thought, once I had recovered my wits, was to call someone – the police, I suppose. And then I realised my phone was gone. I opened and closed my mouth, working the muscles of my face, establishing the level of damage. A wide zone of pain across the right side, a nasty headache from nowhere, but nothing broken. I was fundamentally intact. Hot, sour tears surged up and I fought with them, and the humiliation they brought and that brought them, all across the bright field of Trafalgar Square, and at last they retreated, without spilling, under the white lights of Embankment Station.

Neither of my housemates was home once I got back, which suited me as I had no wish to tell them what had happened and deal with their questions. As well as sore, my face was abnormally hot, and I knew some of that was shame.