The atrium is chaotic and hugely noisy, a dissonance of piped music, shouting children and the chatter of hundreds of people.

Evan takes hold of Matt’s arm.

‘First things first,’ says Matt brightly, trying to keep it upbeat. ‘I need to find the gents. Let’s try over here.’

With Evan’s arm linked through his, he feels protective. People will assume Evan has special needs, which of course he does. Taking a long way round to avoid pushing through a crowd, Matt leads his son to the toilets, and inside.

There are men using the urinal.

This is a place where men do intimate things, hidden away from the outside world. Evan tightens his grip on Matt’s arm.

‘We’ll use the stalls, shall we?’ Matt says discreetly. ‘You go first. I’ll guard the door.’

He senses the other men listening, and almost laughs at the irony that he may be taken for some kind of paedophile. Evan clearly likes the idea of a locked door between himself and the strangers, but he’s reluctant to be parted from Matt, who touches his back, encouraging him forward. His hand there makes Evan uncomfortable. When he pulls away, it’s a stab in Matt’s heart.

But Evan goes into the stall, closes the door and bolts it. Matt’s bladder is insisting he use the urinal, but Evan might be watching his feet under the stall door, so he handles his discomfort and stays where he is, as he’s promised. He waits for Evan to flush, then waits a minute or two longer, but beyond the sound of a zip being done up, there’s silence.

The pressure on Matt’s bladder is becoming critical.

‘Evan, buddy, are you OK?’ he asks. A few moments later the bolt is slipped back and Evan appears.

‘My turn,’ says Matt.

Evan’s eyes grow wide, and Matt sees his fear. Evan doesn’t want to be alone in here.

‘Tell you what,’ says Matt. ‘You go back in there and lock the door, I’ll use the doo-dah over here. One minute max and I’ll be back. OK?’

Evan bolts himself back inside the stall, where the flimsy hardboard walls must feel far safer than no walls at all.

‘One minute!’ calls Matt, unzipping his flies. When he’s done, he taps gently at the door.

‘I’m back,’ he says. ‘Let’s go.’

Behind the hardboard walls Evan is listening, making his decision on whether it’s safe for him to come out. As he’s about to take the risk and slide the bolt, two men burst in, talking loudly about last night’s football. They sound big and rough, the kind of men who’d easily overpower him, so he sits down on the toilet, puts his arms around himself, hugs himself into the smallest shape he can make and waits, quiet and unseen, until they’re gone.