‘I hope the bastard hasn’t got wind of us,’ the DI mutters grimly. ‘We can’t afford not to get him. Not now.’

‘No. Sir, there’s a car coming.’

He freezes briefly as he listens, then mutters into his radio. As we wait, the noise gets louder and then a black BMW estate comes into sight, speeding up the drive and stopping sharply at the gate. Immediately, twenty or so police surround it. Through the tinted glass, I see the driver’s head turning frantically, clearly thinking about reversing before realising the futility of even trying.

The DI pushes through the officers surrounding the car, then knocks on the driver’s window. After a pause, it’s lowered.

‘Philip Mason? Detective Inspector Saunders, Chichester Police. I am arresting you on suspicion of the possession and distribution of pornographic images. You do not have to say anything but it may harm your defence if you do not mention when questioned something you later rely on in court. Anything you do say may be given in evidence.’

Mason’s mocking laugh reaches my ears. ‘Porn isn’t a crime, Detective Inspector. Now let me get on, please.’

‘You’re right, Mr Mason. But possession of pornographic images of children is. Out of the car.’

Behind Mason’s BMW, a police car pulls up.

Maintaining his dignity, Mason gets out and stands in front of the DI. There’s no struggle and his face gives away nothing. A minute later, the police car drives him away.

‘Check Mason’s car, will you, May? Then we’d better get back to the station.’

There’s a briefcase in Mason’s car and a few CDs in the glove compartment, all of which I remove. When I catch up to the DI, he’s talking on his phone. After he’s finished, he glances at what I’m holding.

‘Check the discs as soon as we get back. They might be innocent but I’ll bet they’re not.’

*

As we drive back to the station, something is puzzling me. ‘He was taking quite a risk, wasn’t he – coming back to the house, when he knows we’re on to him?’

The DI stares ahead. ‘I imagine he had to get the cellar cleared out at some point. He wouldn’t necessarily have known we’ve already done it for him. He may have sensed he was running out of time and it was a risk he had to take.’ His face is grim. ‘We’re still no closer to knowing where those children came from. Maybe he can help us with that, too.’

*

Two hours later, after Mason’s lawyer arrives, I join the DI in the interview room.

‘Right. Let’s get this started. I’m Detective Inspector Saunders. This is Detective Sergeant May. We’d like to question you about the contents of a cellar on your property, Mr Mason.’