It is then that William notices Valerie’s perfect left hand. Nothing missing or mashed, no blood, no bruise, not even a scratch. No matter the twisted leg, the missing toes or the indent on one side of her skull. It will be her perfect hand that her parents remember when they have to remember this.

Carefully, he lifts the carotid artery from the neat incision in her neck. He rests it flat on the stainless steel separator, noticing the tiny capillaries tracing their delicate path through the blood vessel. He eases the small artery tube into the cut he has made and then repeats the process with the internal jugular vein. After joining the first to the supply of arterial fluid and the second to a tube leading to a bucket by his feet, William picks up the hand pump. Squeeze release, squeeze release, squeeze release. The fake heartbeat drives the fluid through the girl’s arteries and her blood into the bucket. William’s hand aches from all the pumping. His back aches from leaning over small bodies, but he doesn’t slow down, or stretch his back, or flex his fingers.

Once the body has been aspirated, treated with fluids and the incisions sutured, William breathes deeply. He takes her left hand in both of his and rubs, bending her knuckles, easing the fluid to the very end of the fingertips, rendering them pink again.

‘There we are, Valerie,’ he says, ‘all done.’ He doesn’t mind that Harry, busy now at the next table, can hear. While he continues to hold her hand, he finds himself singing, very softly, barely more than a murmur.

‘I forget all your words of promise
You made to someone, my pretty girl
So give me your hand, my sweet Myfanwy,
For no more but to say “farewell”.’

The last time he’d sung this he was holding another hand. Martin’s, his best friend in Cambridge, who would theatrically grab his whenever they sung it together. ‘She’s Welsh, you idiot,’ he mutters to himself, ‘sing it in Welsh.’ He glances up at Harry, but he is suturing, and doesn’t seem to have noticed his quiet serenade.

‘Anghofia’r oll o’th addewidion
A wneist i rywun, ’ngeneth ddel,
A dyro’th law, Myfanwy dirion
I ddim ond dweud y gair “Ffarwél”.’

William walks to the stack of coffins. The top one is white, flown over with the Irish embalmers. He’s glad. Valerie would probably prefer white. He lowers her into it, arranges her head to one side, covers her body with one of the donated blankets and rests her hand on top of it.

He carries the coffin into the chapel and lays it down on one of the pews, uneasy that Aberfan seems to have resurrected memories of the two people he’s trained himself so rigorously to forget.