The curtain drops, and the intercom buzzes. Ron moves fast to open the door before he misses his chance.

Inside the hallway, the decor is as he’d expect: shabby, drab, depressing. Someone’s left a bicycle at the bottom of the stairs which makes it difficult to move. From somewhere upstairs there’s a smell of curry.

A door on his left opens. The man standing there is again what Ron might have predicted: long hair, funny slogan T-shirt, five days’ stubble, bad teeth.

‘Can I help you, mate?’ he says, in a way which suggests helping Ron is the last thing on his mind.

‘I hope so,’ says Ron. ‘I’m looking for a lady called Jennifer Lambert, Flat Four. You know her?’

‘What’s she done, then?’

‘I’m just asking if you know her.’

The man gives a slow, lupine smile.

‘Don’t give me that. You’re a copper. It’s written all over you. Not the type for trouble, I didn’t think she was. I know ’em all, I do, I see ’em come and I see ’em go. But she’s been gone a while, ’as Jen.’

‘Any idea where to?’

‘She met up with some South African, went to live with him over there. He was a doctor or something, as I remember. That was the last I heard. She said she’d send a postcard, but she never did. Anything I can help you with?’

‘I don’t think so,’ says Ron, opening the front door to let himself out. ‘But thanks anyway.’

The drive from Sevenoaks to Woking takes longer than it should, but once Ron hits the A3, progress improves. As he’s driving, he calls Naylor and tells her he’s found one more dead end.

‘Not going too well, is it?’ says Naylor. ‘Still, you never know. No stone unturned.’

The address in Woking is a terraced house whose front garden has been bricked over for parking. There’s a car parked there now, a bright orange Mini Cooper. As he climbs from his own car, the traffic lights at the end of the road turn green. The waiting traffic moves on and the road falls into a brief hiatus, quiet enough to hear the shouts from a school playing field a couple of streets away.

It was Ron who taught Naylor to be suspicious of doorbells. He knocks, and waits, and in a minute or so a woman answers, a woman pretty good for her age, fit-looking in tracksuit bottoms and a high-vis Lycra top. Her cheeks are pink, as if she might just have been running.

‘Yes?’

Ron gives a bright, non-threatening smile.

‘I wonder if you might be able to help me,’ he says. ‘I’m looking for a lady by the name of Lindsey Stockman.’

‘That’s me.’

‘I’m sorry to disturb you. Is it Miss Stockman or Mrs?’

‘Neither.’