On the evening of May 10, 2018, the second to last carriage of a Victoria Line underground train in London got turned into a guerrilla exhibition featuring twenty-four grainy black and white images capturing the traces of morning commuters. These images were made by artist Alex Stone using a homemade pinhole camera. ‘Intervention I’, as she called it, took place with the aim of subverting this public, yet commercially-dominated space, creating an event as a way to free members of the public from the conventions of the underground and to encourage interactions between strangers. The text below is written by Vanessa Onwumezi and Martin Wakefield in response to the intervention.

Reaching up. Our hands and arms obscure our faces. In rush hour, one hundred people in this carriage – 32 sitting, 68 standing, 8 carriages, a train every 50 seconds in and out of each station on this line. It’s all arms and hands holding on.

We fear. We fear each other’s gaze. We fear, as Perseus knew, we’ll be turned into stone. It’s safe to look only in a mirror. My book is my mirror. My phone is my mirror to the outside, an uneasy peace.

All the thousands of people, in the hundreds of carriages, travelling throughout the spindles and branches of this network carry on the same way. It’s as beautiful as the movement of wildebeest on the plains of the Serengeti or the murmurations of starlings over Brighton West Pier. And yet, no talking, and as the spaces between fill with bodies we draw in, further in, and look down. We are de-individuated within the force field of this crowd and we turn inward to protect ourselves.

Eight in the evening; the journey begins on the blue line, we stop, more people board than get off, the carriage fills. The woman in the black leather jacket with the Baby On Board badge is using her thumbs to type into her phone. She’s saying the man opposite in the grey three-piece with a blue triangle in his breast pocket is typing into his phone saying that the boy with the red-framed glasses and the box-fresh Nikes is typing into his phone saying that the girl in the paisley headscarf and the black jeans is typing into her phone saying that the man with the long grey hair and florid complexion is typing into his phone saying that everyone in the carriage is typing with their thumbs.

With flick after flick of the wrist the photos go up, the ads disappear one after another – Ecover (People said we were crazy), Dave, Addison Lee, Relish (Break free from your broadband), Insure & Go, Pregnacare (Most trusted by mums), Zurich, Iron on Iron – and are replaced by pin-hole images, black and white exposures, blurred faces, hands caught in movement.

Offerings of food and drink – crisps and tonic – go round and a few faces lift from their distractions. There is one that beams. As though his existence has been affirmed. His keen eyes slide over the photos and over them again. Thank you – the sound of ice breaking.

Others look but don’t seem to see, or don’t want to see or be seen. Not today. They leave the carriage, taking their thoughts with them. But to not understand, or say no, is to engage nonetheless, to make a choice about which way you go.

Intervention interrupts the dead, stony gaze, forces itself though the mirror, and guides eyes upward. Intervention brings down the barriers between us, if only for a moment; those social, imaginary barriers which are difficult to surpass. We take the opportunity to be here instead of connecting to the world via reproduced images: the newspaper for the yesterdays, the phone for the now right now, the advert for the thing that we might want, might need, might desire someday. But now, this public view is for us, today.

A couple – woman in blue coat and man, tall and grey – are on their feet. Hands holding blue bars, bodies engaged as they shift along and steady their gait while the carriage gallops on. We are now creatures that use our hands to get around; we hold, we touch, we are alive and we are here. Doors will open on the right-hand side. Nine more people on. Need a hand? Tell us what you think, we say. And now we are a scrum, a ball of people, a small intervention, a shapeless noise, talking, laughing, crunching crisps, sipping tonic.

We take in more than we know, more than we are told: CCTV always in operation, please keep your belongings clear of the doors. Highbury and Islington, it smells of dust. Kings Cross feels warm and clean. Euston has a cold light. Warren Street, yellow tiles. Pimlico is so polite.

Brixton lifts your spirits. We are hurtled through black corridors pushing heavy air before us. Noises are deadened by the soot-laden walls of the tunnels and suddenly the rails screech and the tiled platform echoes the rolling sounds of raw machines.

Intervention asks you to look, to become aware. There are no more adverts, but now, in their place, beautiful and ambiguous, half-ghosted black and white photographs of us, underground explorers of time and space.

A girl with a black suitcase holds her drink and stares up at the image. It’s removed, whipped away as quickly as it came, but her eyes remain fixed, glazed. Where has she gone? Down a tunnel, deep under the earth, yes, but, the fear of petrification lifted, now mindful of the choices she has, the question of her destination has become more urgent. Where are we going? Where will we get off?

What’s at the end of the line? We now come to understand that we are ‘representatives of a species whose mission remains obscure’.