Devil’s Slide school turns out to be a collection of three mural-painted shacks, each smaller than the next, like an Ikea nest of tables which has been allen-keyed into the desert floor at the foot of a cliff. There is a parking area in front, and to the side a field of Indian grasses with the cadavers of six or seven mutilated cars nestled picturesquely amongst them. Behind the shacks gigantic tractor tyres have been imaginatively arranged for traditional playground games. ‘The Swing’ is a tyre suspended by three chains from a wooden construction. ‘The Climbing Frame’ – a bunch of tyres piled one on top of the other; and yet more have been placed at even intervals on the ground to make ‘Stepping Stones’.

We’re the last to arrive. As the door bangs behind us, faces turn. I count roughly twenty-five kids, ranging from Emmy’s age up to around twelve years old. Apart from a couple of wildly beautiful Indian girls, the numbers are about 30 per cent Mexican to 70 per cent white. On the whole the younger children are neatly turned out, with combed hair and pressed jeans. Some of the older kids, though, are a rough-looking lot whose flinty eyes suggest they’ve seen the back of their daddy’s hand more than once.

‘Stetson, Wyatt, Carson, Jesus,’ the teacher reels off names. Until this moment my biggest worry has been that the children are not going to like their school lunch. I’d warned them it could be bean-related, and in anticipation of such a crisis have armed them with baggies full of peanut-butter sandwiches. Now, as the inmates of Devil’s Slide turn their old men faces towards us and fix us with curious if not downright hostile stares, I wonder what on earth I’ve got them into.

In the back row of the class, a pale boy with very blond hair, pellucid blue eyes and a nose plug of crusty snot taps Jack on the arm with the end of a chewed pencil.

‘Hey, you.’ He eyeballs him up and down. ‘How old are ya?’

‘Eight,’ Jack says.

‘Oh yeah?’ The boy looks sceptical. ‘You’re pretty short for an eight-year-old. What class you in?’

‘I’m in PP2W,’ Jack says politely, quoting his London classroom.

‘Listen, pal,’ the kid drawls, ‘if you’re eight years old, you’ll be in third grade like me – you got that straight?’

Jack nods and squares his shoulders. There’s not even the slightest question of me giving him a hug before I leave.

I drive back along the road and pull into the next gas station where, although not in the least hungry, I find myself buying something very nasty called a break-fast burrito – a cling-filmed refrigerated tortilla filled with scrambled egg, beans and onions – which, despite its fifteen-second sojourn in the microwave, is not adequately heated through.