The lady who met us at the top did not have blue-rinsed hair. Actually I’m not sure what blue-rinsed hair would look like, and why did anyone think blue hair was a good idea in the first place? Nor did she have fingerless mittens or too many cats, but there was something about her that suggested that both could be serious lifestyle choices in the future. She was also quite tall for a little old lady, spry and not even slightly senile. She gave her name as Mrs Shirley Palmarron.

We were quickly ushered into a living room that had last been seriously refurnished in the 1970s, and offered tea and biscuits. While she bustled in the kitchen the dog, a short-haired white and brown mongrel terrier, wagged its tail and barked non-stop. Clearly the dog didn’t know which of us it regarded as a greater threat, so it swung its head from one side to the other barking continuously until Nightingale pointed his finger at it and muttered something under his breath. The dog immediately rolled over, closed its eyes and went to sleep.

I looked at Nightingale, but he just raised an eyebrow.

‘Has Toby gone to sleep?’ asked Mrs Palmarron when she returned with a tea tray. Nightingale jumped to his feet and helped her settle it on the coffee table. He waited until our host had sat down before returning to his seat.

Toby kicked his feet and growled in his sleep. Obviously nothing short of death was going to keep this dog quiet.

‘Such a noisy thing, isn’t he?’ said Mrs Palmarron as she poured the tea.

Now that Toby was relatively quiet I had a chance to notice that there was a lack of dogness about Mrs Palmarron’s flat. There were photographs of, presumably, Mr Palmarron and their children on her mantelpiece, but no chintz or doilies. There was no dog basket by the fireplace, and no hair ground into the corners of the sofa. I got out my notebook and pen.