As not seen on television: The millionaire major and his good lady in the hot seat

Will the Major get to keep his cash? Cole Moreton sits in on the trial

Who wants to be a millionaire? You do, of course. So do I. And so does just about everybody in the country who isn't one, which is why the television show was such an enormous hit. It is also why a small, stuffy room at Southwark Crown Court is packed with people. Normally you can stretch out among the two-dozen imitation leather seats in the public gallery behind the dock and watch someone tried for burglary or another ordinary crime. But today it is as hard to find a place in Court Four as it is to get the hotseat opposite Chris Tarrant with a chance of winning a million.

Being asked questions under those glaring television lights with the cameras gazing in to your soul must be like going on trial. So Major Charles Ingram of the Royal Engineers must feel reasonably comfortable in the dock. He looks reasonably calm, leaning forward in his pinstriped suit and tapping to attract the attention of a barrister.

The dock has glass walls but no ceiling. It looks like a bigger version of the sound-proofed cubicles they use in other quiz shows. Beside Major Ingram is his wife Diana, all in black. Their desks are close together, a little away from the third defendant, a college lecturer called Tecwen Whittock. Dressed in a pale suit and tie, he is more anonymous looking than the striking, dark-haired Mrs Ingram and her powerfully-built soldier. All three deny collaborating to "procure a valuable security by deception".

The suggestion is that they "dishonestly procured Christopher Tarrant to sign a cheque for £1 million by deception". Not in some dark corner but in a television studio where every flicker of the eyelid, every twitch of the cheek and – crucially – every cough could be replayed and examined.

Talking of replays, this is one. The trial started on Wednesday but on Thursday a juror was sick and on Friday he was discharged. Then a new jury was sworn in, except luck and a ballot has decreed it should contain 10 people from the original panel. The eleventh – the one who didn't make it – must feel like a quiz contestant eliminated after the first round.

Nicholas Hilliard, for the prosecution, begin his second attempt at a case with a painstaking review of the rules of the programme – even though almost everyone present knows them and heard him the first time. "This is going to hurt me as much as it hurts you," he sighs.

Would-be contestants call a premium rate telephone number, specify the date of a recording, and answer a multiple choice question. A computer selects 100 callers who are then asked another question, and researchers call those who get closest to the right answer. The first 10 they reach are invited to the studios in Elstree where recordings are made in the evenings, with an audience of 199 people. The final hurdle is the fastest finger round.

Recited in calm, legal tones the rules sound like they were devised by Franz Kafka. They underline the feeling in many of our bones that the chances of ever getting into the hotseat are the same as Elvis winning the lottery. That instinct is one reason why the popularity of the show was waning before this court case reignited public interest. Another is that very few people actually win a million – Mr Ingram was the third until the police were invited to investigate. The prosecution suggests he arranged for an accomplice to be 10 feet away in the seats occupied by those waiting to enter the fastest finger round.

In the afternoon the public gallery gets what it craves: a replay of the night the Major won, as never seen on television. "I see no reason why we should be wearing wigs while watching the programme," says the judge for no obvious reason, mopping a slick brow. The robes stay on. The jurors look bemused, but settle back to enjoy a good bit of telly. All sound has been mixed down except the input from the microphones worn by Chris Tarrant and the contestants. The prosecution wants us to listen out for suspicious coughs, timed to suggest answers – so inevitably a number of people in court are seized by the need to clear their throats.

To win £500,000 the Major has to say which city Baron Haussman is best known for planning. Mr Ingram appears convinced it is Berlin. A dry cough is followed by what the prosecution suggests sounds like the word "no!". The Major changes his mind and goes for Paris.

"I am going to play Paris," says Mr Ingram.

"You were convinced it was Berlin," counters Mr Tarrant.

"I know. I think it's Paris."

Paris is the right answer. The Major asks for a moment to recover his composure as they take a break and the court sees what happens while the nation is usually putting the kettle on. Not much, is the answer.

"No discussions, please," says a floor manager to the audience. "There is a serious amount of money at stake."

He's not wrong. On the final question the Major who lives in an army house and has no property of his own gambles £468,000 – apparently on a whim and against his own instinct.

"He initially went for nanomol, he then went through the various options again," Chris Tarrant tells the audience. "He then went for googol because he had never heard of it and he had heard of the other three. You've just won £1 million."

As silver ticker tape falls and the Major is embraced by his wife, Chris Tarrant says he is the most amazing contestant they have ever had. "I have no idea how you did that."

The video stops. The defendants look up. The judge addresses the jury: "Monday morning, half past ten." The case continues.