Cottage has finished her questioning. It is time for the cross-examination. Brian Stork, Marshall’s barrister, rises to address Robert. Marshall leans forward.

“That first term,” says Stork. “You had a house master and a house tutor…” Stork asks a succession of questions about names of teachers and what role they had, as Robert gives brief, clipped answers. He asks Robert if he remembers one particular teacher, who wasn’t Marshall. “He was your tutor,” says Stork.

“Really? I don’t remember,” replies Robert. Stork moves on to locations.

“You’ve told the jury … you visited a particular address. You told police that address was in Twickenham.”

“I remember him living in Twickenham or him doing a house up in Twickenham,” says Robert, unsure where this is leading. His mouth and cheeks have tensed up; his eyes have narrowed, as if awaiting the attack.

“Was it a dead end close to the Thames?”

“I don’t remember.”

“Does the address Denton Road mean anything?”

“It sounds familiar.”

“Was it on three floors?”

“I think it was on two floors.”

The questions continue; it appears Stork is searching for a fact or memory upon which Robert will stumble. Perhaps he wishes to create an impression of unreliability. The questioning morphs into a cross-examination about the extra phone line Robert’s parents installed, and the fact that he shared it with his sister.

“I don’t remember him phoning very much,” says Robert, at which Stork pounces.

“But I thought this all began from his regularly phoning you at home?”

“Yes,” Robert says, explaining that initially this was the case. Stork has made little headway by the time proceedings stop for lunch.

When we return, as we await Robert, Marshall, in the dock, yawns so widely he bears his teeth. He stares ahead. What is he thinking? What does he tell himself? What has he told his wife and children?

Robert is back in the stand. Stork turns to car rides – were there not other boys who rode in Marshall’s car? You don’t remember? – and then to directions and locations, in another confusing interrogation. Your trips away tended to centre on west and southwest London?

“Yes,” replies Robert, almost successfully hiding his irritation.

“You’ve heard of Richmond?”

“I have indeed,” he says, with sarcasm edging in.

“I think you remember the view from the top of the hill?”

“Do I remember the view from the top of Richmond Hill?” replies Robert, almost mockingly.

“You don’t associate looking at a hill with Mr Marshall?” He persists, as Robert continues to sound irritated. Stork lands on the location of their first meeting: Capital Radio. “Why meet at Capital?”

“I can’t tell you,” says Robert – he cannot remember why.

Robert has been in the dock for over two hours by the time Stork questions him about the name of the restaurant on that first meeting, when Robert realises he has got the name wrong: it’s not Chicago Rib Shack but Chicago Pizza Pie. A flaw in his testimony has been found.

The dinner with Robert, his 19-year-old female friend, and Marshall is next. “You told police there were four of you,” says Stork – a contrast to the trio he mentioned earlier to the other barrister.

Robert explains that her boyfriend sat with them for a short while at the start.

The friend, it transpires, does not remember this dinner taking place. “I suggest it didn’t happen,” says Stork.

“I suggest it did happen,” replies Robert, with quiet defiance.

Stork wants to know what Robert’s friend knew about Marshall. Had Robert informed her that the man meeting them for dinner was his teacher from school?

“Yes,” says Robert, and as if suddenly aware of what it is to be an observer to this conversation adds, “It’s quite shocking when you hear it like that.” This perspective changes something; bridging him to the impartiality of a neutral observer – to the jury.

“You told her that one of the teachers had sexually abused you?”

“Yes.”

“Can you remember how she reacted?”

“She wanted to be a grown-up and was accepting. But thinking about it now, I can’t imagine what a 19-year-old would have thought about it.”

The barrister brings up the gold cufflinks Marshall bought. Robert says he pawned them. He seems embarrassed, as if it is the selling of this jewellery that is the grubby act. Marshall shakes his head. Stork moves on.

“Do you remember there were loads of whispers at St Paul’s…” he begins, referring to another boy, who we shall call Andy, and Marshall.

“I remember some, not lots. To my shame I probably said it.”

“You were central to a whispering campaign … were you?”

“No.”

The discussion hones in on Andy, rumoured to have been Robert’s replacement: Marshall’s new boy.

“I was upset about being dropped,” says Robert.

“You were angry because [Andy] had what you had wanted,” says Stork. The implication seems to infect the air.

“I was 15,” Robert replies, trying to curtail his disgust, and says that at that age he had no such desires.

“You took a shine to Mr Marshall, didn’t you?” asks Stork. It does not sound like a question.

“Took a shine?” replies Robert, astonished. “We were having an affair.”

“I suggest you never had an affair,” says Stork curtly. Something switches in Robert, a flicker rising up as he finally faces the iron weight of the establishment.

“Please forgive me for saying this,” he says to the barrister, to the courtroom, and as if to anyone who ever disbelieved him, “But you would say that.” It is a jab of contempt. He pauses. “And yes, it did happen.”

The air in the room shifts suddenly, as if the jury has just seen the rock hit Goliath’s forehead. After this, nothing Stork pelts back at Robert meets its target. “You developed a crush on him,” suggests Stork. “Mr Marshall then suggested you move on to another tutor. Do you remember that?”

“No.”

Stork keeps shooting in the same direction.

“Mr Marshall did not have a relationship with you at all, did he?”

“He did,” replies Robert.

“Any car ride was entirely invented.”

“Absolutely not.”

Stork mentions Denton Road again – the house Robert says he was taken to. “You didn’t visit that address.”

“I certainly did.”

“Mr Marshall did not give you cufflinks.” All Robert can do is contradict, plainly.

“He did give me cufflinks.” Robert stares ahead, frozen: When will this end?

There is one final attempt to deliver a knockout. Stork moves on to the therapist Robert saw in the 1990s.

“Did you say to her that the abuse was when you were in your early teens?”

“Possibly.”

“That’s not true.” A protracted debate ensues about whether 15 constitutes early teens or mid teens. Robert eventually gives in.

“Very well, in my mid-teens. You’re forcing me to say that.”

“I’m not forcing you to say anything,” replies Stork. Finally, Cottage, the prosecution barrister, objects – this is getting nowhere. The judge agrees.

The cross-examination is over. Robert exhales, cheeks puffing out, as he walks back through the court. A few minutes later, the friend who was 19 at the time takes to the stand. Robert has returned to sit in the public gallery and listen.

She is halfway through reciting the oath when her voice gives way. She says she remembers how troubled Robert became, how much weight he lost. “I remember meeting him at Leicester Square. He was wearing dungarees and previously they fitted him but they were hanging off him.” The image lingers. “He was in a very bad way.”

She is struggling to keep control, memories surfacing and gripping as she tries to deliver the words.

“I remember thinking I should contact his mother … I remember hearing the name 'Marshall' continually … I felt there was probably a sexual relationship … I’m very upset with myself,” she says, implying that she should have reported what was happening to someone rather than going along with it, “But I did what I thought was the right thing.”

The dramatic irony is wretched: history howling back. In the years since then, she says, the effects on Robert have never gone away.

She is guided out of the courtroom. Robert has already left. I follow, pushing the door open. To my left he is sitting against the wall, doubled over. His hands are covering his face. He looks up suddenly. His eyes are flooded, bloodshot, streaming.