It had all happened so quickly. After lunch, he had been summoned to a meeting with Mr Davenport and two of the governors. Mr Davenport appeared agitated and struggled to maintain his usual headmasterish bluster. Twice he muttered that it was all a ‘terrible shock’. It took Callum several minutes to understand that yesterday, when he was looking through the presentation, the computer had been connected to the smartboard.

‘We wanted to let you know as soon as possible,’ said the older of the two governors, ‘so that you can look for another position. Not, of course, one involving contact with children.’

The whole ghastly process took less than an hour. His laptop was searched; the slideshow and the three incriminating images of Tamsin were discovered; and this, along with the photograph of Sophie and her written testimony (typed to ensure anonymity), constituted sufficient evidence for him to lose his job.

Callum listened in a state of cold shock. He argued against the allegations even though he knew this was futile; no school would dare to continue employing him in the face of such charges. It was true, he said, that he had put together a presentation about the nude in photography, including a photograph of his girlfriend Tamsin. It was true he had been under considerable personal and emotional strain at the time. But his motives had been entirely educational, designed to develop artistic sensibility in the children. Besides, he had decided not to show them the pictures. They had only seen the slideshow by accident.

‘But you did show them pictures,’ said Mr Davenport. ‘Two terms ago, you showed them pictures from a pornographic magazine.’

‘One picture,’ said Callum weakly. ‘Just one. They were – I found them – the boys were looking at the photographs right there in front of the girls. It seemed, I don’t know, somehow harmful to just ignore the issue.’

‘Can you prove it?’

‘No, of course I can’t prove it.’ Callum was finding it hard to stay calm. He could hear how weak his case sounded. ‘I shouldn’t need to. They’re children. They’re children. I would never do anything to hurt a child, surely that’s obvious.’

Much was made of the cropped picture of the Venus de’ Medici, which – according to the lady governor – looked worryingly like a young girl’s pudendum.

‘I never thought about it like that,’ Callum lied weakly. ‘I mean, it’s a famous work of art, how can that be wrong?’

‘Stupid, Dempster, stupid,’ said Mr Davenport sadly.

‘Will you be involving the police?’ Callum wanted to know.

Mr Davenport look appalled. ‘Good god no, we’re not inhuman. And think of the school!’