There had been plenty of unidentified bodies found in the Peak District during Cooper’s twelve years with Derbyshire Constabulary. Most of them had been young people, and most of them suicides. In E Division, they were generally found soon after death, unless they were dragged from one of the reservoirs. But this woman had been neither.

In profile, the face was cruelly lit. Shadows formed under the cheekbones and in the eye sockets. Creases at the corners of the eyes were picked out clearly in the lights. He could see now that it was a face with a lot of character, marked by life and formed by experience. A woman in her early forties. Someone’s daughter, and someone’s mother.

But the human remains found by walkers in the woods at Ravensdale had lain there a long time, exposed to the weather and the attention of scavengers. The body had decomposed beyond recognition. It had begun to disappear under the growth of moss and lichen, its shape concealed by the blades of coarse grass that had grown through the eyes of the skull.

The head continued to rotate. It travelled through three hundred and sixty degrees, revealing the back of the neck then the opposite profile, finally coming to a halt facing forward again.

‘What about the eyes?’ said Cooper. ‘Are those her proper eyes?’

‘We’ll try a couple of different colours. Blue and brown, perhaps.’

Suzi Lee had cropped dark hair and long, slender hands. She was a forensic artist who worked with the Pathology department at Sheffield University. Cooper watched her fingers stroke the sides of the reconstructed head, as if feeling for the shape of the skull that lay beneath the clay.

‘Blue and brown? We don’t know which?’

‘The eyes are one of the first parts of the body to decompose. There’s no way we can tell what colour they were in life.’

‘It was a silly question,’ said Cooper.

‘Don’t worry about it.’

‘OK. Here’s another one, then – just how accurate is this reconstruction?’

‘Well, like the eyes, the appearance of the nose and mouth can’t be predicted with any confidence, so they’re largely guesswork. If I use a wig for her hair, that will be a stab in the dark, too. But the overall shape of the head is pretty accurate. That’s the foundation for a person’s physical appearance. It’s all a question of bone structure and tissue depth. Look at these –’

She showed him a series of photographs of the skull, first with tissue depth markers glued to the landmark locations, then with a plasticine framework built up around them. The numbers of the markers still showed through the plasticine like a strange white rash.

‘Let’s hope it’s good enough to jog someone’s memory, anyway,’ said Cooper.

‘I take it this is a last resort?’ said Lee. ‘Facial reconstruction usually is.’

‘The clothes found with the body had no identification. There was no jewellery, or other possessions. And no identifying marks on the body, obviously.’