‘Would you like a drink?’ She gestured to the bottles in her hand. Coca-Cola – the real thing, in curvaceous glass bottles like the ones I’d seen shiny, happy Americans with white-toothed smiles selling on the television.

‘Who are you?’

She gave no indication of having heard me. Maybe I’d spoken too quietly. She walked over to the table and put the bottles down, then using the opener she flicked the caps off each in turn, the cola fizzing loudly as she threw them onto the table. One bounced across the iron fretwork and fell with a tinny clink against the paving stones.

‘I think I should go.’

‘If you leave, I’ll tell my mother you broke into our house and I found you rifling through her jewellery box.’

Horror mushroomed inside me so violently I thought I might be sick.

‘Your mother?’ I didn’t understand. They didn’t have a daughter. Mum had never mentioned one. There was nothing in the house that indicated they had children − no photos, no clothes, no posters in any bedrooms. Was she lying?

‘Yes. My mother. More’s the pity.’ She sat on one of the chairs and lifted her bare feet onto the table and crossed them at the ankle. I’d never seen toenails painted purple before and never heard of people wearing rings on their toes, but she wore three and her nails were the colour of autumn plums.

‘Are they here?’ My voice quivered. Why had I been so careless? How stupid could I be?

‘My mother’s shopping while my father gets something fixed on the Jag. A tyre or, God, I don’t know, something dull. My mother will already be in a filthy mood because she won’t have found anything worth buying and will be moaning about Cornwall being stuck in the Dark Ages and wondering why anybody ever leaves Chelsea.’

‘My mum can’t lose her job,’ I whispered.

She stared at me for a moment or two, her expression flat, but then her body seemed to soften.

‘Relax.’ Her voice had lost its sharpness. ‘You don’t need to worry. I’m not going to tell them. I don’t give a shit about you swimming in the pool. I mean, why wouldn’t you? It’s hot as hell today.’

I could have cried with relief.

‘Go on. Stay for a bit. I’m literally dying of boredom. You can leave before they get back.’ She pushed one of the bottles towards me. ‘Have a Coke.’

‘I’ve never had a real Coke, only the one they do at Wimpy.’ And even then I’d only tried it once, though I didn’t tell her that.

She furrowed her brow and a bemused smile flashed across her face as she reached for the bottle nearest her and tipped it up to her lips. I inhaled sharply, shocked by how much she resembled Mrs Davenport in that split second. As I stared at her I noticed other similarities between her and her parents. Her face was the same shape as his. The sweeping curve of her neck was identical to hers. How stupid not to see these things immediately. Stupid not to have guessed who she was. Their daughter. Her house. A surge of irrational jealousy shuddered through me like an electric charge.