Reluctantly Tilling beckoned him through. A glance at the place showed why he was so reticent. The carpet was grubby and threadbare, mended in places with gaffer tape and littered with crumbs, dust and hair. The place smelled of body odour; sour and enduring. It felt like the windows hadn’t been opened in years. Dust lay thickly around the edge of the room, with just a well-trodden footpath past a builder’s jack right in the middle, bracing a metal joist against a cracked ceiling. Wickens took in a leather-effect three-piece suite, extensively repaired with tape, behind which stood a bald car tyre and some tools, balanced on a badly scratched and oil-stained sideboard. The only well-cared-for object was the wall-sized flat screen TV, on which Emmerdale was showing. Wickens was finding the noise of the TV distracting, and said so. Tilling picked up the remote and muted it.

‘Take a seat. Want a coffee?’ His voice was deep and rough.

Dragging his eyes away from the domestic drama portrayed in larger than actual size, Wickens looked again at the grubby and sagging sofa, and eyed the unspeakably filthy kitchen off to the right. ‘No, I’m fine thanks. This won’t take long. So may I ask what you were doing by the river at that time of night?’

Tilling scratched his head, sending a shower of dandruff onto the well-dusted shoulders of his T-shirt. ‘I was hoping to spot an otter.’

‘Are there otters in the Thames?’

Tilling nodded. ‘One or two. I’ve got pictures,’ he said proudly.

There was a voice from upstairs. Wickens didn’t catch what was asked, but Tilling clearly did. ‘It’s the police, Mum. About some dead body in the river.’

Straining for the reply, Wickens heard a little better. I told you to call them.

‘But why? I didn’t see anything,’ he called back up. ‘I didn’t see anything,’ he repeated to Wickens.

‘You mean otters or people?’ Wickens asked.

‘There were people. Too many for otters to show themselves.’

‘Can I get some details down about timings?’ Wickens asked.

‘What do you want to know?’

‘What time you arrived at the riverbank, and what time you left.’

Tilling scratched his head again. ‘Won’t it be on the cameras you recorded my number plate on?’

Wickens sighed and looked at his notebook. This was like pulling teeth. ‘Yes, sir, but I’m anxious to get your own estimation.’