He stepped close, and the way she flinched when she got a rancid blast of his beery breath gave him a little bit of satisfaction.

‘It’s going to be a long night, sweetheart, and I could murder a nice cup of tea.’ Carrington winked at the other detectives. ‘So, be a love, pop back to the station and make us all a nice flask.’

The guys from CID sniggered and the girl’s cheeks reddened. With embarrassment or anger, Carrington couldn’t tell – and didn’t care. He had wasted enough time and had a job to do.

‘Let’s get this over with.’ He walked towards the farmhouse. ‘I met Swann, trust me, he ain’t going to give us any trouble, the man wouldn’t say boo to a goose.’ He clapped an armed officer on the shoulder. ‘You’re with me.’

The interior of the farmhouse was as grim and dilapidated as the exterior and he felt his shoes stick on the tacky hallway carpet. His colleagues moved quietly upstairs and into a kitchen on the left.

‘Jerry Swann,’ he called. ‘Are you here? It’s Detective Inspector Peter Carrington from Essex Police, Jerry. We’d like to talk to you.’

He walked unsteadily along the narrow corridor beneath the sallow light of a single bulb, crooked shadows conspiring with his headache to give it a lopsided aspect like a Krazy House at a funfair, and tried not to brush his shoulders against the curling wallpaper covered with ancient framed photographs. The overpowering smell of damp and drains made him gag. He sensed the armed officer at his shoulder.

‘Jerry!’ Carrington stopped. He heard something coming from ahead. Voices.

At the end of the corridor was an open door, with dark steps leading downwards.

‘Torch.’ He gestured to the officer, and a light winked on behind him, revealing a set of stone steps. Someone was crying below – it was a girl’s voice – and his stomach churned.

Heart pounding, Carrington took the worn, slippery steps carefully, making sure to hold on to the wall. At the bottom, he signalled to the officer to stay out of sight.

Then he walked into the cold, dismal basement, squinting into the glare of light from the naked bulb in its ceiling cage, and saw the wiry figure of Jerry Swann standing against the far wall. He was holding a knife to a teenage girl’s throat.

‘Jerry.’ Carrington stepped forward, toeing a dirty blanket on the concrete floor. Knowing there was an officer with a weapon outside the door, he opened his arms so Swann could see he was unarmed. ‘Come on, son, let’s talk about this.’

The detective ran his tongue along his parched lips. He wasn’t a man who was ever lost for words – everyone knew he could talk the hind legs off a donkey – but the sight of the girl in Swann’s grasp was a shock.