Turnmill Street turned out to be leafy and gentrified. Most of the early-Victorian houses were fully smartened up with crisp white paint and window boxes and brass or blue enamel numbers. There were too many cars for the available parking spaces. As Jack and I walked along, looking for number 27, a BMW glided beside us in search of a slot. But I knew which house was going to turn out to be Audrey’s long before we reached it.

It stood almost in the middle of the terrace. The stucco of the gatepost was a scabby mess of rotting plaster reminiscent of peeling skin, and ivy crawled over the low wall of the garden and fingered the pavement. In the front garden itself, instead of clipped bushes and paving stones, there were an old bath and some geological strata of ancient sodden cardboard boxes. The house itself looked like a decaying tooth in the white smile of the terrace. Buddleia sprouted out of the walls where damp stains from the broken gutters marked the brickwork. The sills had once been cream-painted but were now cracked and blistered, and the windows were so nearly opaque with dirt that the loops of torn curtain inside were hardly visible.

Jack stood in the gateway, head cocked to one side like one of his birds.

‘Shall I knock?’ I murmured to him. There was no bell push and the door itself was an alluvial green that hadn’t seen a paintbrush for at least forty years.

‘Of course,’ Jack answered.

I tapped and then, when there was no response to that, I hammered with my closed fist.

The door suddenly swung open and Audrey stood there. ‘Oh, it’s you.’ She glared.

‘Weren’t you expecting us?’

‘Kids come knocking and then run off.’

I glanced up and down the quiet, well-heeled street. ‘Really? It doesn’t look that sort of a neighbourhood.’

‘They used to,’ she said. The change of tense made me understand that she had lived here for many years, staying exactly the same while her surroundings had relentlessly risen in the world. ‘Do you want to come in?’ She addressed the invitation to Jack rather than me.

He was peering round us both, trying to see into the shadows inside. ‘Yes, please,’ he said smartly.

We followed her down a dusty hallway to the back of the house. In a long narrow room that looked out on to the back garden were a sink and an oven, a folding-leaf table and some upright chairs, two ancient armchairs, a radio and an old portable television set with its hoop of an aerial set at a hopeful angle. This was obviously where Audrey spent her time. More geological strata, this time made of yellowing newspapers, were built up on every open surface. And everywhere I looked there were cats.

‘Do you like animals as well as birds?’ Audrey asked Jack.

He nodded.