The heat was unbearable. There was a thermometer attached to the wall of the terrace in the lee of La Grange and Mark stared at it in disbelief. The mercury was nudging forty degrees and it was only mid-morning.

‘Le canicule!’ Corinne called out cheerfully.

She was sitting at the little wrought-iron table in the shade of the house, a woven bag collapsed by her feet. One foot was tucked up on the seat so she could rub oil into the skin of her calf which was deeply tanned. In her presence he felt pale and watery and acutely Irish.

‘What’s that?’

‘Heatwave,’ she translated, offering up her gap-toothed grin. She seemed perfectly unperturbed by the fug of hot air thickening around them.

‘Putting on your sunscreen,’ he remarked, and she laughed.

‘Eczema,’ she explained, capping the bottle with brisk efficiency and then getting to her feet.

She stretched out her leg, toes pointing like a dancer, and said: ‘You see? It is very ugly, no?’

There was a small patch of scaly skin near her ankle, inflamed from scratching. The oil on her leg glistened in the sun. In her denim cut-offs and white T-shirt, she looked fresh and at ease while he was sweating. He had always thought her gawky, but now he saw that her legs were thin but shapely, her eyes lively, and he was struck momentarily by her coltish beauty.

‘Does it itch?’ he asked.

‘A little. At night, mostly. Sometimes I wake up and it is bleeding.’

‘Right.’

‘It’s best in the water. When I’m swimming, I don’t feel anything. And my diving is spectacular!’

She giggled at her own boastfulness, pointing and flexing her foot, then twirling on the spot with arms outstretched. When she came back to face him, she dropped a small curtsy that was so obviously cute and flirtatious, he was momentarily disarmed.

‘Take my photograph?’ she asked suddenly, producing her smartphone from the back pocket of her shorts and handing it to him.

She issued him with some brief instructions and then stood with her arms stretched towards the sun, eyes closed, face lifted to receive the warm rays, smiling serenely. He took the picture and said: ‘There.’

She came to stand beside him, cupping her hand around the phone to view the image. Satisfied, she told him she’d Instagram it, and then put her hand out and touched his forearm. Briefly, their eyes met, and he felt hot with confusion.

‘I am roasting!’ she declared loudly. Putting a hand to the back of her neck, she lifted her hair. ‘I can’t wait to get into the river!’

Inside the house, the others were getting their swim bags ready. There was a bathing spot further upstream that Val had promised to take them to.

‘What about you? Will you swim?’ she asked, smiling up at him. ‘Will I show you my dives?’