Even Cooper thought he detected a slight hesitation before the reply. Fry was quick to cover it, but it might have been too late.

‘Yes, ma’am.’

The superintendent looked grim. She turned to the notes on her desk and wrote a couple of sentences in small, tight, angry letters that were impossible to read, especially upside down and from this distance.

Branagh glanced up again. ‘Were you aware that Mr David Palfreyman’s granddaughter Melanie had formed a relationship with the Brindleys’ son, Evan?’ she said. ‘A relationship that was disapproved of on both sides?’

There was no need to worry about looking truthful now. The news came out of the blue.

‘No, ma’am.’

‘We had no idea.’

Branagh nodded slowly. ‘There was no love lost between Palfreyman and the Brindleys, by all accounts. Our information is that Alex Brindley came across Mr Palfreyman in the village pub and told him in no uncertain terms to get his granddaughter away from their son. Insults were uttered, angry words were exchanged. We’re treating that as a possible motive for Mr Palfreyman’s actions.’

The two detectives sat silently, having nothing to say. The superintendent scowled in irritation.

‘Would either of you like to comment on that scenario?’

They shook their heads.

‘No, ma’am,’ said Fry.

‘Then you’d better leave, DS Fry. We’re finished here.’

A team of detectives had broken out their stabbies for the raid. They were piling into vehicles to meet the armed support unit at a rendezvous point close to the site of the meth lab in Staveley. Fry and Cooper walked straight into the CID room to join them, and no one objected. They’d been part of the enquiry from the beginning.

Cooper fell into step alongside Fry as they followed DI Hitchens out to the car park.

‘Diane, why were you protecting David Palfreyman back there?’ he said quietly.

‘Why?’ Fry secured her stab vest with a final, violent jerk. ‘Why? How the hell do I know?’

Cooper wondered if she really did know. Not only had David Palfreyman carried out his own form of justice. But it seemed to Cooper that he had also saved their lives.

The location of the raid was a small, run-down industrial estate on the outskirts of the former pit town. A single unit had been identified as the target, rented by a man named and confirmed as a known suspect in the Sheffield drugs trade. The unit was sited towards the back of the estate, but the service road ran straight up to its rear entrance, where a white van stood parked in front of sliding steel doors.