The car screeched into a parking space in front of it, and everything stopped. Ed let out a long breath and glanced at the clock. It was six minutes to twelve.

‘This is it?’

‘This is it.’

Jess appeared suddenly paralysed, as if she couldn’t believe they were actually there. She undid her seatbelt and stared at the car park, at the boys strolling in as if they had all the time in the world, some reading off electronic devices, others accompanied by tense-looking parents. They were all wearing the uniforms of minor public schools. ‘I thought it would be … bigger,’ she said.

Nicky gazed out through the dank grey drizzle. ‘Yeah. Because advanced maths is such a crowd-puller.’

‘I can’t see anything,’ said Tanzie.

‘Look, you guys go in and register. I’ll get her some glasses.’

Jess turned to him. ‘But they won’t be the right prescription.’

‘I’ll sort it. Just go. GO.’

He could see her staring after him as he skidded out of the car park and headed back towards the city centre.

It took seven minutes and three attempts to find a chemist large enough to sell reading glasses. Ed screeched to a halt so dramatic that Norman shot forward and his great head collided with his shoulder. He resettled himself on the back seat, grumbling.

‘Stay here,’ Ed told him, and bolted inside.

The shop was empty, aside from an old woman with a basket and two assistants talking in lowered voices. He skidded around the shelves, past tampons and toothbrushes, corn plasters and reduced Christmas-gift sets, until he finally found the stand by the till. Dammit. Why the hell hadn’t he checked whether she was long- or short-sighted? He reached for his phone to ask, then remembered he didn’t have Jess’s number.

‘Fuck. Fuck. Fuck.’ Ed stood there, trying to guess. Tanzie’s glasses looked as if they might be pretty strong. He had never seen her without them. Would that mean she was more likely to be short-sighted? Didn’t all children tend to be short-sighted? It was adults who held things away from them to see, surely. He hesitated for about ten seconds and then, after a moment’s indecision, he pulled them all from their rack, long- and short-sighted, mild and super-strength, and dumped them on the counter in a clear plastic-wrapped pile.

The girl broke off her conversation with the old woman. She looked down at them then up at him. Ed saw her clock the drool on his collar and tried to wipe it surreptitiously with his sleeve. This succeeded in smearing it across his lapel.

‘All of them. I’ll take all of them,’ he said. ‘But only if you can ring them up in less than thirty seconds.’

She looked over at her supervisor, who gave Ed a penetrating stare, then an imperceptible nod. Without a word, the girl began to ring them up, carefully positioning each pair in a bag. ‘No. No time. Just chuck them in,’ he said, reaching past her to thrust them into the plastic carrier.

‘Do you have a loyalty card?’

‘No. No loyalty card.’

‘We’re doing a special three for two offer on diet bars today. Would you like –’

Ed scrambled to pick up the glasses that had fallen from the counter. ‘No diet bars,’ he said. ‘No offers. Thank you.’

‘That’ll be a hundred and seventy-four pounds,’ she said finally. ‘Sir.’

She peered over her shoulder then, as if half expecting the arrival of a prank television crew. But Ed stabbed out his PIN, grabbed the carrier bag and ran for the car. He heard, ‘No manners,’ in a strong Scottish accent, as he left.

There was nobody in the car park when he returned. He pulled up right outside the door, leaving Norman clambering wearily back onto the back seat, and ran inside, down the echoing corridor. ‘Maths competition? Maths competition?’ he yelled at anyone he passed. A man pointed wordlessly to a laminated sign. He bolted up a flight of steps two at a time, along another corridor, and into an anteroom. Two men sat behind a desk. On the other side of the room stood Jess and Nicky. She took a step towards him. ‘Got them.’ He held up the carrier bag, triumphantly. He was so out of breath he could barely speak.

‘She’s gone in,’ she said. ‘They’ve started.’

He looked up at the clock, breathing hard. It was seven minutes past twelve.

‘Excuse me?’ he said to the man at the desk. ‘I need to give a girl in there her glasses.’

The man looked up slowly. He eyed the plastic bag Ed held in front of him.

Ed leant right over the desk, thrusting the bag towards him. ‘She broke her glasses on the way here. She can’t see without them.’

‘I’m sorry, sir. I can’t let anyone in now.’

Ed nodded. ‘Yes. Yes, you can. Look, I’m not trying to cheat or sneak anything in. I just didn’t know her glasses type so I had to buy every pair. You can check them. All of them. Look. No secret codes. Just glasses.’ He held the bag open in front of him. ‘You have to take them in to her so she can find a pair that fits.’

The man gave a slow shake of his head.

‘Sir. We can’t allow anything to disrupt the other –’

‘Yes. Yes, you can. It’s an emergency.’

‘It’s the rules.’

Ed stared at him hard for a full ten seconds. Then he straightened up, put a hand to his head and started to walk away from him. He could feel a new pressure building inside him, like a kettle juddering on a hotplate. ‘You know something?’ he said, turning around, slowly. ‘It has taken us three solid days and nights to get here. Three days in which I have had my very nice car filled with vomit, and unmentionable things done to my upholstery by a dog. I don’t even like dogs. I have slept in a car with a virtual stranger. Not in a good way. I have stayed places no reasonable human being should have to stay. I have eaten an apple that had been down the too-tight trousers of a teenage boy and a kebab that for all I know contained human flesh. I have left a huge, huge, personal crisis in London and driven five hundred and eighty miles with people I don’t know – very nice people – because even I could see that this competition was really, really important to them. Vitally important. Because all that little girl in there cares about is maths. And if she doesn’t get a pair of glasses that she can actually see through, she can’t compete fairly in your competition. And if she can’t compete fairly, she blows her only chance to go to the school that she really, really needs to go to. And if that happens, you know what I’ll do?’