The Riverside Inn was a sprawl of a building that had accreted around a solid sixteenth-century half-timbered core. Its restaurant was well known and it was best, I was informed, to book in advance to avoid disappointment. Fortunately you could get snack type food for eating in the pub garden, although their idea of cheese on toast was mature cheddar melted onto a slab of brioche and topped with mustard seeds and cress. As well as a garden terrace, the inn kept a strip of lawn hard on the riverbank just by the stone bridge and it was there I found Beverley relaxing at a wooden picnic table with the aforementioned posh cheese on toast and an open bottle of Bordeaux. She offered me a glass as I sat down.

‘Try it,’ she said. ‘It’s on the house.’

‘Can’t,’ I said. ‘I’m on duty.’

‘So you are,’ she said, and poured herself another glass.

A smart-looking white girl in a black skirt emerged and on Beverley’s recommendation I had the steak baguette which practically came with a genealogy of the cow and a half-page essay on fresh bread making in Northern Herefordshire. After all that, it was probably just as well that it was delicious if a bit under-seasoned by my standards. Beverley waited till I had a mouthful before asking me to keep an eye out, and without another word she lay down on the bank and stuck her face and head in the water. I swear she stayed in that position for over a minute, her locks waving like seaweed in the current.

I was just about to tap her on the shoulder when she straightened suddenly, an arc of water from her hair spraying back into the car park and landing on the bonnet of an overheated Mondeo where it sizzled.

‘Social call?’ I said.

‘Nobody home,’ said Beverley, flicking out her locks. Water made a sheen on her neck and shoulders and soaked the top of her T-shirt so that the zip of her sports bra poked through the material.

‘Sad really,’ she said.

‘What is?’ I asked, standing clear as Beverley flicked her locks again and tied them back with a waterproof scrunchie.

‘The terrible Teme trio told me about it,’ she said. ‘The spirit of the river was done in by Methodists in Victorian times. That really pissed them off – Miss Tefeidiad said you expect that kind of behaviour from the English, but Welsh boys should have known better.’

My phone pinged and let me know that my restatementing of Nicole and Hannah’s friend had been actioned. I told Beverley, and asked if she wanted to be dropped off somewhere.

‘Can I come to the interview?’ she said.

‘How would I introduce you – “Hello, my name’s Peter Grant. I’m with the police and this is my colleague Beverley Brook who is a small river in South London?” ’

‘You used to introduce me like that,’ said Beverley.