Cooper nodded. ‘Yes, I suppose it is.’

It wasn’t exactly a technical assessment – but accurate, all the same. There were many occasions when a police officer in E Division might want to use it. A Saturday night on drunk patrol, for example. Another body lying in the gutter on the High Street? I’m not touching that, Control – it’s yucky. Yes, that would work.

But today was his rest day, and he’d volunteered to take his eldest niece out for the day, since the Christmas holidays had started. So he had an obligation to be interesting and informative. Volunteered? Was that really the right word? His recollection was that he’d happened to be hanging around at Bridge End Farm chatting to his brother Matt, when Amy had kidnapped him. But he’d never prove that in court. He had no evidence.

‘The “hand of glory” supposedly comes from an executed criminal and was cut off the body while the corpse was still hanging from the gibbet,’ said Cooper, reading from the guide book.

‘There’s a recipe here,’ said Amy, interrupting him. She was eleven now, and strangely adult in some ways. Cooper was starting to feel sorry for the teachers at Amy’s new school. She could be merciless if you were boring her.

‘A what, Amy?’

‘A recipe.’

‘Like Delia Smith? That sort of recipe?’

‘I suppose. “The recipe for the preparation of a hand of glory is simple,” it says.’

Cooper looked down at his niece, surprised by the sudden change in her tone. Now she was interested. It was yucky just to stand and look at a preserved hand, but learning how to preserve one yourself – now that was cool. He supposed he shouldn’t be surprised.

‘“Squeeze the blood out of the hand. Embalm it in a shroud and steep it in a solution of saltpetre, salt and pepper for two weeks. Then dry in the sun.” What’s saltpetre, Uncle Ben?’

‘Erm … I’m not sure.’

Amy snorted gently. ‘“The other essential item is a candle made from hanged man’s fat, wax and Lapland sesame.” What’s Lapland sesame?’

‘Erm …’

‘Sesame seeds from Lapland, obviously.’ She frowned. ‘Do sesame plants grow in Lapland?’

‘I, er …’

‘Never mind.’

‘I know how the hand of glory was used,’ said Cooper desperately. ‘You fixed candles between the fingers of the hand, and then you lit them when you broke into a house.’

‘When you did what?’

‘Well, it was used by burglars. According to the legends, it made them invisible. It was also supposed to prevent the owners of the house from waking up.’