I wanted to meet her again, but everything about her was almost too elusive. At the Holiday Inn, beside the placid waters of the artificial lake, she had been nervous and aggressive, a little too devious about her reasons for attending my father’s funeral. At the same time I was sure that she wanted to tell me something about his death, perhaps more than I cared to know.

The entire evening had been an elaborate ruse, a clumsily handled tour of Brooklands and its accident black spots. She had known that the race riot would take place, and wanted me to witness it. But was she trying to warn me away, or recruit me into her suburban conspiracy? Dissembling was so large a part of middle-class life that honesty and frankness seemed the most devious stratagem of all. The most outright lie was the closest one came to truth.

Thinking about this moody young doctor, I carried my whisky into the utility room. I was slightly drunk as I gazed at the silent computer and the biographies of fascist leaders. I rested my glass on the ironing board and touched one of the St George’s shirts. Almost without thinking, I picked up the shirt, shook it loose from its geometric folds and pulled it over my head.

I stood in front of the mirror, aware that the street brawl had made my skin glow. My father’s shoulders had shrunk in his last years, as I had seen from photographs of him, and the shirt gripped my chest like the embrace of an approving parent.

I SAT IN MY CAR outside Brooklands High School, waiting until the last of the pupils had left. Swarming past me, they filled the nearby streets with their noise and anarchy, a teenage rabble that would soon take over the world. I liked them all, the cruel and scruffy lads with their surrealist humour, and the cruel and queenly girls.

When the teachers had driven away I left the car and walked down the drive littered with sweet wrappers, cigarette papers and cola cans, the debris of an amiable plague. I entered the main hall, still echoing with the shouts and catcalls, filled with the reek of testosterone and unlaundered sports gear.

The head teacher’s secretary confirmed my appointment. Assuming that I was a would-be parent, certain to be disappointed at this oversubscribed school, she was cheerful and sympathetic. She told me that Mr Sangster was in the library but would join me shortly.

I waited outside his office for fifteen minutes, then set off in search of the head teacher. I guessed that William Sangster, one of Duncan Christie’s three witnesses, was none too keen to meet me, having done his bit to set free the man about to be charged with my father’s murder. Even a lifetime’s coping with disagreeable parents and education committees would be little help in dealing with a son desperate for revenge.

The library was a warren of dog-eared books, billets-doux and cigarette butts stubbed out in alcoves. Sangster had left a few seconds before me, and I listened to the sound of retreating feet in a corridor. I walked past the empty classrooms, nodded to a teacher marking exercise books beside her blackboard, and saw a tall man in a black overcoat turn quickly towards the gymnasium.

We crossed the sprung wooden floor together, separated by fifteen yards of polished surface but in step, taking part in a form of remote dancing. Sangster moved briskly, but I caught up with him as we entered a block of sixth-form classrooms.

He gave up with a resigned flourish and waited for me to join him, brushing the dandruff from his overcoat. He was an unnecessarily large man, with heavy arms and shoulders and a plump, babyish face, far younger than I expected. He avoided my offered hand, and I wondered if he was an impostor, a thirty-five-year-old actor who had somehow taken charge of a sink school and was already looking for a way out. He noticed my feet avoiding three condom sachets on the floor.

‘We’ve . . .’ He affected a mild stutter, pointing to the sachets, and smiled bleakly. ‘We’ve . . . taught them something. Mr—?’

‘Pearson. I have an appointment. Richard Pearson.’

He stared at my raised hand, as if I were trying to sell him a sex aid, and moved a deeply bitten forefinger from his babyish lips. ‘Right. Your father . . . ?’

‘. . . died after the Metro-Centre shooting. You were there.’

‘I remember.’ Sangster stared at the condom sachets. ‘Tragic, absolutely. You have my sympathies.’

He beckoned me into an empty classroom and led me on a tour of the form, then indicated a desk in the front row. When I sat down he prowled along the blackboard, pausing to erase a numeral in a maths equation, clearly one of those large men who never seem to know what to do with parts of their bodies. He looked down at his left arm, as if discovering it for the first time, unsure how to fit the limb into his mental picture of himself.

Impatient to get to the point, and tired of humouring this rather odd man, I said: ‘Mr Sangster, you’re obviously busy. Could we . . . ?’

‘Of course.’ He sat in the form master’s chair, and gave me his full attention, smiling in a genuinely friendly way. ‘Two of our parents were injured that day, Mr Pearson. You desperately want to find who killed your father. But I’m not sure there’s anything I can do.’

‘Well . . . in a sense, you’ve already done it.’

‘Is that so? How?’

‘You helped to clear Duncan Christie.’

Sangster sat back, head resting against the maths equation, tolerating my rudeness. ‘I testified that I saw Christie in the entrance hall when the shots were fired. I didn’t help to clear him. It’s not in my gift. It was an eye-witness statement.’

‘You were actually in the Metro-Centre?’

‘Naturally. There were two other witnesses who testified.’

‘I know. For some reason, that bothers me.’ Trying not to unsettle this highly strung head teacher, I put on my friendliest account-executive smile, a grimace I had hoped to abandon for ever. ‘You all knew him. Isn’t that odd?’

‘Why?’ Chair tilted back, Sangster watched me across the form master’s desk, blowing out his plump cheeks like a puffer fish estimating the size of its prey. ‘We wouldn’t have recognized him otherwise. Why would we pretend we’d seen him?’

‘That’s the nub of the problem. It’s difficult to think of a common motive . . .’

‘Mr Pearson, are you suggesting we conspired to free Christie?’ Sangster touched the blackboard behind his head, pretending to half-listen to me. ‘Three respectable witnesses?’

‘You are respectable. Almost too respectable. It’s possible you saw someone like Christie. You might think you saw him, and naturally you feel he’s innocent.’

‘He is innocent. Mr Pearson, I taught him. For three years I was his maths teacher, in this very classroom. In fact, he sat at that desk where you’re sitting now. Someone fired those shots, but not Duncan Christie. He’s too unreliable, too erratic. He does odd jobs for me, mending the fence or mowing the lawn. He works hard for five minutes and then his mind sails off, he drops his tools and disappears for a week. His brain is a kind of theatre, where he plays games with his own sanity. He did not shoot your father.’

‘Right.’ I eased myself out of the ink-stained desk. ‘As it happens, I agree with you.’

‘You agree? Good.’ Sangster stood up and brushed the blackboard chalk from his coat, reversed equations falling into dust at his large feet. He gestured me to the door. ‘But why . . . ?’

‘I saw him outside the magistrates’ court. He was acting the killer, just to wind everyone up. He only stopped when he recognized me and knew it wasn’t a game. The real assassin wouldn’t have done that.’

‘Well put.’ Sangster nodded sagely. ‘You’ve been through a lot, Richard, and you’ve kept your focus. It may look like a conspiracy, but many of us knew Duncan Christie and we didn’t want to see him framed . . .’