The only major players who’ve not been signed up by Celador are the defendants. Three thousand journalists have approached the Ingrams for interviews. Although I am way ahead, being a close family friend, I note that many other reporters have their own ingratiating tactics, and I’m not resting on my laurels. On Day One, for example, Charles entered court and gave his solicitors a kind of victory salute: a punch in the air. Half a dozen journalists, me included, thought he was punching the air at us, so we performed slightly awkward victory salutes back. It was a little embarrassing.

A few feet down the corridor, the reporters gather in a circle, comparing notes. “I liked it when Charles said the charges were ‘absolute rot,’” says one journalist. “Do you think we can get away with having him say ‘tommyrot’?” says another. Everyone laughs.

It is agreed that Hilliard is a brilliantly scathing cross-examiner. A passing barrister on his way to Court 5 tells me that Hilliard “trounced me in a murder trial once.” I didn’t think to ask him whether the convicted murderer did it or not.

Tecwen Whittock sits far down the corridor, sometimes alone, sometimes with his son, Rhys. He’s so unassuming that I never once see him enter the dock. He just seems to materialize. I wander over to him.

“I’m from Cardiff too,” I say.

“That’s a coincidence,” he says.

“And my mother went to Howell’s,” I say.

Howell’s is the private school Tecwen sent his daughter to, running up a £20,000 bill. This debt, say the prosecutors, was Tecwen’s motive.

“See?” says Tecwen. “That’s another coincidence. Coincidences do happen!”

“I was at prep school with Adrian and Marcus Pollock,” I say.

“That’s another coincidence!” says Tecwen. “I’d like to see what Hilliard would do to you, with all those coincidences, if he got you on the stand.”

I don’t tell Tecwen the fourth coincidence—that Judge Rivlin is a distant cousin of my mother’s.

I wander down the corridor to talk to the arresting officers. “Is this trial really worth it?” I ask Detective Sergeant Ian Williamson. “I mean, come on, in the end, what exactly did they do? Why didn’t Celador just settle their differences with the Ingrams in a civil court?”

This is the worst question you can ask an arresting officer. They hate ambiguities. The police have a lot to lose if this trial goes badly for them. Some of the arresting officers were Paul Burrell’s arresting officers. They really need a success after that fiasco.

“This trial,” Williamson replies, crisply, “is about protecting the integrity of the Millionaire format. Millionaire is the most popular quiz show in the history of television. Celador has sold it to a hundred countries. Thousands of jobs depend on its success. . . .”

This is true. In fact, a BBC reporter down the corridor has just returned from Jordan, where she was meeting Palestinian leaders. They asked her why she was going back to Britain. “It’s to do with a quiz show called Who Wants to Be a Millionaire?” she said. The Palestinian leaders got really excited and said, “The Coughing Major! You’re going to that trial?”

So I understand what Williamson means, but another thought occurs to me. The prize money Charles allegedly tried to cheat out of Celador came from the revenue generated from the premium-rate phone lines—the calls the viewers make in their frequently fruitless attempts to get on to the show. So it is revenue generated from the far-fetched hopes and dreams of the viewing public, which seems like a cheat in itself. And how much is this trial costing? The answer is around a million pounds. If there’s a guilty verdict, we the viewing public stand to lose a million pounds. If there’s a not-guilty verdict, Celador will be forced to give Charles his check back.

“Watching that cross-examination has taught me,” I say to Detective Sergeant Williamson, “if I’m ever in a situation like that, I’m going to plead guilty.”

There is a small silence.

“Proper criminals do,” he replies.

Every morning sees a scrum for the public-gallery seats. I secure my place each day because I arrive an hour early and I don’t budge, even though I often very much need the toilet. Charles’s father, himself an army man, sits next to me. He wears a tiepin shaped like a steam train. Unyielding pensioners with flasks of coffee mercilessly nab most of the other seats. One regular keeps passing me notes. I tend to open them with great anticipation. It is exciting to be handed a note in a courtroom. Today’s note reads: “Is your suit made out of corduroy?”

The pensioners spend much of the day noisily unwrapping packets of Lockets and readjusting their screeching hearing aids. A young man behind me cracks his knuckles from 10:00 a.m. to 4:00 p.m. Each time the barristers mention the word “cough”—and the word “cough” is mentioned very frequently—many people sitting around me involuntarily cough. We are like a comedy-club audience, determined to enjoy ourselves even if the comedian isn’t very funny. Even Chris Tarrant’s reading of the oath gets a loud chuckle from a man behind me.

Chris Tarrant may not be the world’s greatest superstar, but within the context of this grubby building we’ve come to call home, the wallpaper peeling, the soap in the toilets as hard as rock, the evidence dragging on and on, he is a vision of paradise entering Court 4.

“Has anyone ever got the first question wrong?” asks one defense barrister.

“It’s happened in America,” replies Tarrant, to huge laughter around the court. Tarrant looks surprised. He was just giving a factual response. During all the merriment, the fact that Tarrant heard no coughing, suspected no foul play, and even said to the show’s producers, “Don’t be stupid,” when he was told of their suspicions, seems to have got lost.

Rod Taylor, Celador’s head of marketing, gets a big laugh, too, during his evidence about how he frisked Charles shortly after he’d “won” the million. Taylor offers to frisk one of the barristers to show him how he did it. That gets a laugh. In the dock, Charles begins to cry.

“Why then?” I ask him at Starbucks the next day. “Why did you cry at that moment?”

I often meet Charles and Diana at Starbucks. I discovered early on that if I happen to be there at 9:05 a.m., this is exactly when Charles queues up. We make small talk. Five minutes a day. That adds up, in my reckoning, to a substantial exclusive interview.

“It was when Mr. Aubrey [Tecwen Whittock’s barrister] was cross-examining Rod Taylor and he said something and everyone laughed,” replies Charles.

“What did he say?” I ask.

“He made a joke,” says Charles. “Here I am, this cataclysmic event, my family on the line, and everyone is laughing. And you know how I feel about not wanting to look stupid.”

“What was the joke?” I ask. “What was the exact thing he said that made you cry?”

Charles pauses. Then he says, “It was when Mr. Aubrey said to Rod Taylor, ‘Did you search his privates?’”

•   •   •

THIS STORY BEGINS in 2000. Tecwen Whittock was watching Who Wants to Be a Millionaire? one night when he recognized a contestant but couldn’t remember where from. I could have told him. It was my old school pal, Diana’s brother, Adrian Pollock.

“That’s the same guy,” Tecwen realized, “who was on a few weeks ago. He’s been on four times now! I think I’ll track him down and ask him what his secret is.”

Tecwen is a quiz-show veteran. He keeps a journal of trivia, of random facts and figures accrued over the years. He’s been on Fifteen to One, although he was eliminated in the first round. He didn’t fare much better on The People Versus. He managed to Beat the Bong, whatever that means, but still only won £500. Sale of the Century was another disaster. “I convinced my wife I’d win a car, but in fact I won the booby prize of a world atlas,” he later tells the court. He had, however, once made it to the semifinal of Brain of Britain.