Still the man thrashes against him, wild as a trapped animal. His arms flail; his shoes scuff against the damp gravel of the canalside. His feet gain purchase. His legs lock. His rigid torso thrusts into Billy’s chest. It’s a powerful blow and Billy staggers backwards at its force. They’ll both end up in the water at this rate, he thinks. But he must keep tight hold of the rope. This is his very life he’s holding onto; he’s come this far and nothing will make him let go now.

The man writhes, cries out – choked, desperate. He clutches at the rope to try to prise it from his failing throat. The twine chafes against Billy’s knuckles, sends blood slick across his aching white fists. The man gives a guttural cough, an internal retching that seems to come from Billy’s own chest. Together they lurch, wrestling twins, a two-headed beast, until the man’s scrabbling boots blanch under the street light. Billy freezes. They have left the cover of the bridge. Someone might see.

With a roar, he drags his raging victim back to the dark, heels scoring twin trails in the loose stone chippings until, to his relief, the shadow of the bridge slides over them once again. Billy’s nostrils flare; his mouth gapes. Not enough air; he must suck in all he can. Overhead comes the rubbery rhythm of cheap shoe soles on stone. One person only – the brisk, offended strut of a good-time girl who has heard one joke too many tonight. Soon there will be more people along this way. He must hurry.

The man bucks, his belly rounding like a bedsheet on the breeze. With all his strength, Billy pulls the rope. He has begun to cry, to sob with a kind of grief. It is all so wretched, but he has not been able to grasp the exact nature of the wretchedness until now. This is how it is to kill a man. This is how it feels.

His body is numbing with cold and pain. His nose is running; no hands free, he has to lick away the gritty trail of mucus from his upper lip. His wet hair falls into his left eye. He flicks his head to clear it, but it falls back. He blows it up, this stubborn lock, but it drops again as soon as his breath fails. It is so bloody awful, this business of death. It wasn’t meant to be this hard. It wasn’t meant to be this messy.

He yanks at the rope again, and this time, at last, the writhing stops. Billy could let go of the rope now, but no, it is not worth the risk. He will finish this, and after it is over, then will be the time for putting things right. Then will be the time for atonement.

‘I will do only good.’ His voice is little more than a croak; his biceps sear for lack of oxygen. ‘Only good from now on. I swear by Almighty God.’

He gives one last pull. The rope is in spasm, his hands in spasm with it. His teeth hurt; he fears he might press them into his gums. He cannot hold on.

The tang of urine fills his nostrils. The man collapses. His feet splay, his body heavy as a gravestone. Silence rushes under the bridge and stops there, filling the space with its terrible sound. Billy clutches the rope, but already the tension is gone.

‘Only good now,’ he says, and falls to his knees. ‘Only good from now on. Oh God.’

Footsteps overhead: clack, clack, clack – the whinny of tipsy female; the bass notes of the male who thinks his luck is in. Billy’s chest is a pump. The jagged path digs into his knees. If those above could see him here below: filthy and crying, snot-smeared and pitiful. What foul troll is that? they would ask themselves. What monster?

He sucks at the cold damp air, air that smells of moss and dirt. Monster. With his bloody hands he wipes his face but feels only mud and grit. Monster. He is still weeping: for this death, for his own saved life. If they could see him, if anyone could, oh God.

The pain of the evening’s exertions claws at his bones. He must rally. He hauls himself to his feet, tries to lift the body, but it is too heavy. He has to kneel again and push with all his remaining strength to roll it towards the water. It now. At the edge, he stops. He can feel the ugly set of his own disgusted mouth. His skin itches and cracks. He closes his eyes for a moment. He is already kneeling, as if the decision to pray has been made for him.

‘Lord God,’ he whispers, closing his hands together, hoping he can remember at least some of the words. ‘As we commit the earthly remains of our brother to the earth… that is, to the water, grant him peace until he is raised to the glory of new life promised in the waters of baptism. We ask this through Christ our Lord. Amen.’

A strong shove is all it takes to roll the body over the side. Barely half a second passes before the dull splash of oblivion breaks the quiet. Billy groans, lies full length on his stomach and stretches his hands into the water. Scooping up handfuls, he splashes his face clean. Baptism, he thinks. I baptise myself. I am born again.