As I turn away my toe catches on something and I look down. There’s a patch of burnt grass beside the bench with stones at the edges and three or four charred logs in the centre, where a fire must have been. I dip down and hover my hand above them. Cold. Whoever started the fire is long gone. But there was someone here, someone who needed to light a fire to keep warm. The sound of voices cuts through the wind’s whistle and the roar of the traffic and I freeze, my hand still stretched towards the logs. The voices are too close to have drifted up from the pub. And they’re male voices, young male voices. My walk becomes a jog as I rejoin the path, then a sprint as I realize that the sound is coming from directly below the bridge.

I slow to a halt as I get closer: I can still hear the voices but there’s no obvious way of getting to them. The foliage is thicker here with bushes and trees reaching way above my head. And then I spot it, a disturbance in the bracken and a stamped-down path leading directly under the bridge. The voices grow louder as I crash through the undergrowth and then someone shouts, ‘Whoa,’ as I burst into a small clearing on the riverbank. Four teenagers, sitting cross-legged around a fire with their bags and bikes scattered around them, stare back at me. There’s a shocked silence, then one of them giggles. He stares at me, his eyes big and round, then tips backwards, his arms wrapped around his body as he explodes with laughter.

‘Naz, you dick!’ The boy to his right picks up a can of lager from beside his friend’s head and turns it upside down. ‘That was the last of my beer.’

‘Lost your dog?’ says another of the boys. He dips his head and takes a puff on the spliff hidden in his curled hand.

‘No, I …’ Behind the boys is a concrete column. Even in the dim light I can make out the swirl and curve of the graffiti at the base.

‘Graffiti fan, are you?’ says the boy with the spliff as I take a wide circle around the group to take a closer look. In two places someone has written the initials DBK in thick orange paint. There are some nonsensical letters sprayed in purple along the centre of the column. CNSCS, that’s all I can make out. ZYNK is written in black spray on the lower strut of the column and there’s something in a white bubble shape with black edging. I can’t read a word of it.

‘Do you …’ I turn back to the boys. ‘Do any of you do graffiti?’

‘“Do you do graffiti?”’ Spliff Boy repeats, totally deadpan, and Laughing Boy howls with amusement.