‘Some parents would take a dim view of that,’ he says. ‘They might be led to think you’re a man without too many scruples. I’ve got someone out looking for David Sellers, so we’ll see what he has to say when we track him down. In the meantime, I expect we could drum up another cup of coffee while you wait.’

‘If you’re lucky, we might even throw in a couple of Hobnobs,’ says Dallabrida.

‘I want a lawyer,’ says Mr Griffiths.

In the classroom, Naylor is seated at the teacher’s desk. The playground shouts and screams beyond the window take her back years, but there’s no smell of chalk and over-boiled dinners here. Times have moved on, to whiteboards and interaction, and the sandwich she bought for lunch in the canteen earlier was grilled chicken on ciabatta.

The man coming through the doorway is dressed casually, without the tie the headmaster insists male teaching staff should wear. His beard is blurred into several days’ growth of stubble, and his crooked teeth are ugly and discoloured as a smack addict’s. But he seems pleasant enough, diffident, eager to please, softly spoken.

‘I hope I’m not late?’ he says.

Naylor glances at her watch, and at the list of school staff she’s been given.

‘Mr Prentice?’

‘That’s right, that’s me. Gary Prentice. Gareth at birth. People like to shorten it to Gary.’

‘Have a seat, Mr Prentice.’

He lays a hoop of keys on the desk and sits down in front of her, smiling unselfconsciously, in spite of his teeth.

‘Thanks for taking the time to talk to me.’ Naylor turns to a fresh page in her notebook and writes Gary Prentice’s name at the head of the sheet. ‘It’s just routine. We’re talking to everyone on the school staff as part of our enquiries into Evan Ferrers’s disappearance.’

‘It’s very unsettling, especially for the parents,’ says Prentice. ‘I don’t have children myself, but I’m sure it must be a worry.’

Naylor looks at him.

‘A little more than worrying, I should say.’

‘I’m sorry, yes, of course. It’s hard to know what word to use.’

Naylor glances at the notes she’s made on her list.

‘Mr Mullis tells me you haven’t been caretaker here very long.’

‘About six months.’

‘And before that?’

‘I was at a school in Guildford.’

‘And you left there why?’

‘I was made redundant. The school I was at merged with another, and they already had a caretaker. He had longer tenure than me, so I was out. I was lucky to find this job. Good school, nice area.’

Naylor makes a line of notes.

‘Were you in school yesterday evening?’

‘I was,’ says Prentice. ‘There’s no time off for me, in term time.’

‘And did you see Evan and Stewie Wareham at all?’