Image copyright BBC/PA/Getty Image caption Clockwise from top left: Chris Martin of Coldplay, Craig David, Toploader, A1

See if you can answer the following multiple-choice question: Who had a hit UK album with Born To Do It, released in 2000?

A) Coldplay

B) Toploader

C) A1

D) Craig David

Most pop music fans would be able to identify the correct answer (D) fairly easily. Born To Do It was a huge album which spawned several hit singles.

But former British Army major Charles Ingram had no idea who Craig David was when he was asked this as a contestant on ITV gameshow Who Wants To Be A Millionaire? in 2001.

He admitted as much as he mulled over the possible answers to the £32,000 question.

"I think it's A1," he told host Chris Tarrant. "I've never heard of Craig David, to be honest. Coldplay I've never heard of. I think I'll go for A1."

So it was a surprise to everyone when he suddenly changed his mind and opted for Craig David as his final answer, seemingly for no logical reason.

Image copyright Getty Images Image caption Diana and Charles Ingram pictured outside Southwark Crown Court in 2003

It was an even bigger surprise when he got all his subsequent answers correct as well, ultimately winning the show's £1m jackpot.

But Ingram never received the prize money.

The episode had barely finished recording when producers worked out he had an accomplice among the waiting contestants, who had been coughing every time Ingram read a correct answer aloud.

If the accomplice, Tecwen Whittock, didn't know an answer, Ingram's wife Diana would cough the correct answer from her place in the audience.

All three were later found guilty of deception after a lengthy trial at Southwark Crown Court in 2003.

"It was this incredibly audacious heist," says writer James Graham, who has adapted the coughing scandal into the three-part ITV drama Quiz.

"I thought of it like Ocean's Eleven or Mission: Impossible, but with very middle-class people in Wiltshire.

"And instead of abseiling down skyscrapers they had encyclopedias and it was about questions and answers. But essentially it's still about the robbery of a million pounds."

Image copyright ITV Image caption Sian Clifford and Matthew Macfadyen play Diana and Charles Ingram

The ITV drama is directed by Stephen Frears and stars Matthew Macfadyen as Major Ingram and Fleabag star Sian Clifford as his wife Diana Ingram.

Graham first told the story of the coughing scandal in his stage version of Quiz, which played in Chichester before a successful West End transfer in 2018.

He tells the story the same way on TV as he did in the theatre: twice.

The first half of the stage show (and the first two episodes of the drama series) basically assume Ingram was guilty - which indeed was the finding of the courts.

But the second half explores the possibility that he might have been innocent, and there is some evidence to support that theory.

"He was painted in the press as an idiot, someone who couldn't have possibly known the answers to those questions," recalls Graham.

"But you forget that he has a degree in engineering, and he applied to be accepted into Mensa and succeeded, thereby putting him in the top 2% of IQs in the country."

Image copyright Johann Persson Image caption Quiz started life as a stage play, which transferred to the West End in 2018

Added to that, the coughs heard during the correct answers weren't the only coughs heard during the recording. There were plenty of coughs from audience members when incorrect answers were read out.

Helen McCrory, who also features in the ITV drama, points out: "Chris Tarrant didn't hear the cough, people either side didn't hear the cough, yet for some reason [Major Ingram] heard the cough, I mean, really? Now maybe he did, maybe it was a complete set up. But maybe he didn't."

Graham and the production team were in touch with the Ingrams while the drama was being filmed, and the couple visited the set and met Clifford and Macfadyen, the actors who would be playing them.

"Diana Ingram was painted as this Lady Macbeth character, and I don't think that's who she is," Clifford says. "She struck me as an introvert and a nerd, and someone who's actually quite shy, quite sweet, definitely naive."

Most of the cast seem at least open to the possibility that the Ingrams could be innocent. But host Chris Tarrant thinks there is no doubt about the couple's guilt.

"I sat through so many hours with the police and fraud squad of tapes of the major's show, and he is so guilty," he told This Morning in November. "It's like once you lock into it, it's like oh, for god's sake."

Tarrant is played by Michael Sheen in the new ITV adaptation.

Image copyright ITV/Matt Frost

Image copyright PA Media

Graham says the fact the drama is airing on ITV, the channel on which the scandal occurred in the first place, didn't affect how he wrote the story.

"I never had a single note [from them], they were such good sports all the way through, even though they knew from the beginning that one of the central propositions is 'were they right?' And is the perceived narrative that they were responsible for telling entirely correct?

"But I think there is a mischief in putting it on the broadcaster which was responsible for the story, and it also frees you up to do certain things."

Quizzing network

The TV series explores an element of the story not well-known before - the existence of a small network of quizzers around the country who would share tips about how to get on to the show and reach the jackpot.

The group, who called themselves The Consortium, realised that Millionaire's researchers would always ask the same general knowledge questions over the phone when they were screening potential contestants.

The Consortium shared the answers between themselves, increasing the chances of each of getting on the show.

They even offered a bespoke service where a contestant could ring a number via their "phone-a-friend" lifeline, and their small gang of general knowledge experts would be on hand to pose as their friend and provide the answer.

The drama's exploration of this group, and Ingram's contact with them, further encourages the assumption that he was guilty.

When Quiz was running as a stage show, the theatre audience was given keypads and asked to vote at the end of the first half - and then again at the end of the second half - on whether they thought the Ingrams were guilty or innocent.

"The audience always said at the beginning that they thought they were guilty," notes Graham. "But then by the end of the play, every single night, they converted to innocent.

"Except, weirdly, for matinees, we don't know why," he laughs. "Obviously a different crowd."

Quiz begins on ITV at 21:00 BST on Monday 13 April.