“The water people seem to think eight o’clock tonight’s going to be the most dangerous time,” Mower said. “They want the area cleared by six.”

“A good enough reason to get an emergency warrant to search the place then,” Thackeray said, and cut the connection.

“Is this official now?” Dizzy asked Mower. The sergeant shrugged.

“Looks like it,” he said. “Though I’m not sure what the Super’ll make of our little surveillance.”

It was a couple of minutes later, as they sat watching Jake and Barry Foreman himself ferry more boxes and packages to the Land Rover, that Dizzy B took Mower’s arm.

“We’ve got trouble,” he whispered, pointing to the side of the building where it was just possible to see a slight figure crouching in the shadows watching events just as they were doing from the other side of the street. Jake and Foreman went back inside the building together, leaving the doors half open and casting a single beam of light into the storm.

“I’ve a very nasty feeling I know who that is,” Dizzy said. “And last time I saw him, as you’ll recall, he was in possession of a serious looking automatic.”

“Stevie Maddison,” Mower groaned. He called Thackeray again.

“I’m on foot three minutes away at the end of the street,” the DCI said. “Don’t do anything till I get to you.” But his instruction was too late. While Mower had been distracted by his phone call Dizzy B had opened the car door and was already sprinting, dreadlocks flying, through the ankle deep water which now spread right up to the front steps of the office buildings on the other side of the street. Mower watched, horrified, as the boy in the shadows, instead of fleeing as he expected, turned towards Sanderson and fired. Sanderson swerved but did not appear to be hit as the boy turned and made for the open doors of Foreman Security Services and dodged inside, closely followed by the DJ.

“Where are they?” Michael Thackeray asked as he pulled open one of the rear doors of Mower’s car and dropped into the seat behind him, water dripping from his hair and jacket. “Where’s Sanderson? I thought you said he was with you?”

“He is, he was, he’s gone playing James Bond,” Mower said. “Sorry, guv, I couldn’t stop him. He’s chasing after the kid with the gun and this whole operation’s going pearshaped.”

“No way,” Thackeray said. He used his own mobile phone this time to call headquarters and summon up armed officers and as many other reinforcements as could be mustered in the middle of a civil emergency. “If that bastard’s Foreman’s got a Land Rover full of drugs out there we’ll hang him out to dry.”

“Great,” Mower said. “But at this precise moment he’s also got Dizzy and a fourteen-year-old boy in there and at least one of them’s armed.”

But even that no longer seemed to be the case as Foreman himself came out of the building holding a coat over his head to protect himself from the driving rain, ran down the steps and jumped into the four by four and drove off, swerving wildly through the water as he accelerated.

“Don’t worry, he won’t get far,” Thackeray said. “Come on, we’d better take a look.” Procedure might have dictated waiting for reinforcements but Mower was not in a mood to argue. The two men waded across the flooded road and, as they approached the building carefully from one side, the door was flung wide open and they could see Dizzy B on the top step waving wildly in their direction.

“I couldn’t stop him,” he shouted. “I was too fucking late.”

“Where’s the gun?” Thackeray asked harshly.

“It doesn’t matter now, does it?” Dizzy B replied, and it looked as if his cheeks were wet with tears rather than rain.

They followed him through the reception area into an office with several workstations and immediately saw why he was so distraught. Stevie Maddison lay where he had fallen in front of a desk, his gun still clutched in his hand and a single bullet wound to the side of the head matting his short fair hair with rapidly darkening blood. His blue eyes were still open, gazing sightlessly at the world with a faint look of surprise in them, his jeans and t-shirt, sodden from the rain, clinging to a skinny body which appeared heartbreakingly small to the men crowded above him. The man Mower knew as DS Jake Moody lay sprawled on the other side of the room, close to a doorway leading to the rear of the building, his white shirt soaked with blood, another gun at his feet. Mower crouched down and felt his neck for a pulse.

“He’s just about alive,” he said feeling a flicker beneath his fingers. “He’s our undercover man,” he said. “Drug squad. Name’s Moody.”

“So what’s the fuck he doing shooting kids?” Dizzy screamed at Thackeray. “What the fuck’s going on? And where’s the other bastard who was here just now, the bastard who ran?”

“Taken care of,” Thackeray said shortly, using his mobile to ask for an ambulance urgently. He glanced around the room.

“Did you see exactly what happened?” he asked. Sanderson shook his head, looking dazed now as the full enormity of the situation sank in.

“I heard the first shot as I came through the door,” he said, his voice husky now. “I kept down, man. I’m not kidding you. Over there, behind the reception desk. Then more shots and one guy ran out and after that nothing, silence.” Thackeray nodded.

“This is a crime scene,” Thackeray said pointedly to Dizzy B, glancing at Stevie Maddison’s huddled body and wondering if it would ever be possible to establish who was assailant and who was victim here. “I want you to wait outside till the ambulance and the heavy mob turn up and tell them what’s happened. Kevin and I have something we must do before this place floods and evidence gets washed away.”

They had all been conscious since they had entered the building that there was a rushing noise coming from further inside. As Dizzy B turned away to go outside, shoulders slumped, Thackeray led Mower further back through the offices until they traced the noise to an open door leading to descending stone steps. The rushing sound became louder, drowning out coherent speech but Thackeray did not hesitate, leading the way down steps into a cellar where a single lightbulb still burned. The floor was dry except for a damp trail of footprints from the steps to the corner where a heavy metal plate had been lifted to reveal what Mower realised must be Bradfield’s hidden waterway, rushing beneath them with terrifying force.

“Why?” Thackeray mouthed at Mower pointing at the trail of water. He hurried to the manhole and lay flat on the floor, his face, as he leaned into the cavity, splashed by the torrent, making it even harder to see anything at all. Reaching around as far as he could stretch, he realised that on the downward side of the icy cold flow there was something solid. He could make out the mesh of a thick wire cage of some kind, which had been attached to the roof of the culvert that for large parts of the year carried no more than a modest stream of water down to the River Maze.

Suddenly something pale bobbed into view and wedged itself against the mesh. Thackeray reached forward to catch it but it was not easy to estimate the distance in the near-darkness and, after a frantic second’s scrabbling at the edge of the manhole trying to regain his balance, he pitched forward into the stream head first and the rushing water closed over his head.

Shouting incomprehensibly and uselessly against the noise of the water, Mower flung himself flat and leaned as far as he dared into the opening, sick with fear and not seriously expecting ever to see Thackeray alive again. But to his astonishment after a few seconds he found that he could just make out the DCI wedged against some sort of grille with his nose and mouth barely above the waterline. More often than not the swirling stream rose and hid him completely, but every time he emerged again, his head bent under the culvert’s stone roof, fingers clinging grimly to the mesh behind him, coughing and choking but undoubtedly still alive. If the mesh gave way, Mower thought, he would be gone, carried helplessly for the mile or so it took the culvert to carry the torrent back into the open air of a rocky defile between the hills on the eastern side of the town, and no doubt drowned long before he reached the open air.