Only three cars in front of us now. Papers and passports are being passed backwards and forwards, car trunks being opened and checked. If I hadn’t been able to talk my way out of a speeding ticket, I haven’t got much chance of getting through this. I think of Winfred ripping me off twice and, wondering whether a bribe might be in order, surreptitiously transfer my bag to my lap. I’m not exactly au fait with the going rate for bribing officials in Nogales, let alone the methodology, but surely it will need to be handled subtly, the money passed over with skilful sleight of hand and a knowing look. Already the car in front is being waved through the barrier and I’m so busy siphoning the last few bills out of my wallet and stowing them up my sleeve that I misjudge the distance to creep forwards and overshoot the line. It can’t be by more than a few inches but you’d think I’d come roaring through the checkpoint with a hand grenade in my hand and the pin in my teeth for the reaction it provokes.

‘Whaddayathink you’re doing!’ screeches the customs officer. ‘Get back over the line, GET BACK!’ He’s a chunky American with freckled skin and bulbous eyes showing a little too much white around the pupil. I hastily reverse. ‘No, not that far! Move forwards!’

I jerk forward again until I’m about an inch from where I first stopped.

‘Do you think this barrier is a joke?’ He punches a button and a line of spikes shoot out of the ground right in front of the wheels. ‘Do you want to get yourself killed? It’s dangerous up here! The line is for your own security!’ He jumps out of his box and stalks over to the truck.

In normal circumstances such officiousness would have me giggling behind my hand, but with no passport, no weapon of identity and dressed still in my pyjamas with a sweatshirt on top, I cower behind the steering wheel while he takes a long stick with a mirror stuck at one end and pokes it up the truck’s backside.

He straightens up. ‘There’s a lot of mud on this vehicle. Where have you been driving it?’

‘In Arizona. I live—’

‘Citizenship?’ he interrupts.

‘American?’ I mumble hopefully.

‘Passport.’ He holds out his hand.

My heart sinks. ‘Look, I don’t mean my passport’s American, I mean my passport is, in fact, English, it’s just that I’m living—’

‘Passports,’ he repeats. ‘All of them.’

I chance an explanation. I mention doctors and fits and spasms, reiterate just how truly close to life and death this whole episode has been, turn round and point at poor little sick Emmy who needless to say is now sleeping soundly, her fever making her look as pink and healthy as a baby flamingo.