‘Perhaps you’re not the only one with a file. The details of a police officer’s history are well recorded. Everything is available, if you have the right contacts.’

Maggie advanced, and Fry retreated, trying to keep more than an arm’s length between them. Her instructors had always said the same thing – in a knife fight, you first had to accept that you might not avoid getting cut.

She backed up against a gate and turned too quickly to keep her balance. She felt her ankle twist and pain shoot up her leg. Her foot went numb, and for a moment she lost control of her right leg and had to drag it with her round the corner of the pen. Maggie kept advancing, walking steadily, until she had backed Fry beyond the occupied pens towards the empty fatstock ring, away from the noise and the crowd. Fry risked a glance over her shoulder and saw that she was reversing into the end of the passage. Behind her was the gate into the ring. She briefly considered taking a stand and relying on the chance of deflecting the knife with her baton. But realistically, she knew that her best hope was to gain time until support arrived.

In a ceremonial kata, with two opponents equally matched and wary, you had to watch for the opportunity, the first opening that would enable a strike. Movements became rhythmic and formal, just as they did now. But for Fry, the first opening she allowed could be her last. She had to watch the knife, refuse to be distracted by Maggie’s eyes. She had to keep Maggie talking.

‘Maggie, put the knife down.’

‘You can’t tell me anything about memories either, Diane,’ said Maggie. ‘I know what memories are. I know now that Ros is dead.’

‘But how did she die, Maggie?’

Maggie lashed out suddenly with the knife, a casual sideways stroke without even looking where she was aiming. The blade sliced through the side of one of the plastic barrels as if it had been paper. A sweet, sickly smell filled the passage.

Fry glanced at the tear in the plastic for only a second before she recognized the attempt at distraction, and then she quickly met Maggie’s eye again.