‘Sir, by the grace of God, good day to you,’ the pardoner sings out each time he feels their glances settle too heavily on one or other of them, and each time the traveller nods and returns the greeting and moves on with a blessing, as if all were well.

Katherine stares back at them resentfully, and after a time the pardoner touches her elbow.

‘We’re strangers here, Sister,’ he says. ‘If someone takes against us, they will denounce us for some crime, and without our friends to vouch for our good name, we will end up like this poor fellow.’

He gestures towards a tree where a crowd of birds mob something hanging from the branches. It is a man’s body, hanging near naked, mottled and erupting with decay, his braided guts spilling out like fistfuls of grey string. A bird with glossy feathers clings to its face and with each peck the corpse twitches on its rope. The smell of rotting meat is thick and sweet.

‘Been there about ten days,’ the pardoner guesses.

‘But why doesn’t someone bury him?’ Katherine asks through her fingers.

‘He’s posted as a warning to others.’ The pardoner shrugs. ‘Were it a witch they would just strangle her at the roadside and leave her for the dogs. In the south when they catch a thief they nail his ear to a post and give him a knife to cut himself free.’

They walk on through mist that is shrinking towards the river, leaving a sodden, level landscape interrupted by meagre stands of trees, a low-beamed cottage and a herd of oily sheep. Ahead the town is a gathering of church spires and roofs under a pall of dark smoke.

‘The town of Boston,’ the pardoner says. ‘Home to a thousand or so souls. We must get through it to reach the harbour.’

She hesitates.

‘Come on,’ the pardoner encourages. ‘Walk on the far side of the mule, so the captain of the gate can’t see you. And hold its rope, so that if he does, he’ll think it belongs to you, and that you’re worth something after all.’

They join the other travellers queuing behind a carter trying to get his oxen on to the bridge.

‘Hoc opus, hic labor est,’ the pardoner mutters. He is looking anxious.

At the far end of the bridge a fat man in a stained leather jerkin and an iron helmet stands under a wooden awning, while another with a bill takes coins from those crossing the bridge.

‘Good day to you, sir!’ the pardoner calls when they reach the second man, and he presses a coin into the outstretched hand. The man says nothing but frowns and shows the coin to the first man. The first man holds up his arm to stop the flow.

‘Never seen you before, master?’ he says. His gaze travels over the mule, to Katherine, to Thomas, then back to the pardoner.