'As an afterthought, I decided I should do a £1 each-way acca - I won £550,000'

This article was originally published for Members' Club Ultimate subscribers on Sunday. To read more great articles from our award-winning team of journalists, join Members' Club Ultimate here.

Twenty-five years ago, Frankie Dettori's life was changed forever in a single afternoon. So too was racing history. A quarter of a century later his Magnificent Seven is no less magnificent.

Dettori went to Ascot on Saturday, September 28, 1996, as the reigning champion jockey. He was there for the Festival of British Racing, a seven-race card highlighted by the Queen Elizabeth II Stakes, in which Godolphin's retained rider was booked to partner 2,000 Guineas winner Mark Of Esteem.

Dettori won that race and all the other races. It was an epoch-making achievement. Prior to Dettori, only two jockeys – Sir Gordon Richards and Alec Russell – had gone through an entire British card undefeated, but they did that at fixtures with only six contests. The nearest comparison to what took place at Ascot occurred at Stockbridge on June 18, 1867, when George Fordham won six of the seven races and dead-heated on an odds-on favourite in the other, only to then lose in a run-off.

Ascot commissioned a statue to mark the achievement of Frankie Dettori's Magnificent Seven

Fordham was not fresh in people's minds 129 years later at Ascot. This was Dettori's day. It made him a global superstar, his 25,095-1 seven-timer costing the betting industry an estimated £30 million. Not surprisingly, a number of those who were there retain vivid memories of what they saw – not least one particular racecourse bookmaker.

Gary Wiltshire earned most of his income from laying greyhound bets at Milton Keynes. He was due there that Saturday night but first planned to work at Worcester's afternoon jumps meeting – until, that is, he got to the M40's Banbury junction and found the motorway was gridlocked.

Gary Wiltshire
I rang my clerk, Peter Houghton, and told him we would be better off going to Ascot. I said we might nick a few quid on the rails and get a day's wages. I didn't actually have a pitch at Ascot but, unfortunately for me, there were two vacancies that day and I was the last man to get a spot. I really was a small bookie and only went with a float of £3,000.

Darren Yates is now a well-known owner. At that time he was a self-employed joiner who worked hard during the week and enjoyed a bet at the weekend. That particular Saturday he was due to play for Slyne-with-Hest in a local league football match. Before that, he went into the William Hill shop near his Morecambe home. In total, he placed two bets on Dettori's seven mounts totalling £62. He also chose to pay the tax on those wagers, taking his outlay to £67.58.

Darren Yates
I was mainly interested in backing the Godolphin horses. It wasn't the Frankie factor that most interested me, but after I saw he was riding the four Godolphin horses I decided to back all seven of his mounts. I had placed the 50-pence Super Heinz and was walking out of the bookies when, as an afterthought, I decided I should do a £1 each-way acca as well.

Good publicity: punter Darren Yates celebrates winning half a million pounds on his hero Frankie Dettori's greatest dayCredit: Edward Whitaker

Around 250 miles south, legendary BBC broadcaster Sir Peter O'Sullevan met up with colleague John Hanmer in the Ascot press room at around 11am. Hanmer assisted O'Sullevan as his right-hand man in the commentary box. He would end up doing more than that a few hours later. First, though, O'Sullevan suggested they enjoy some alcoholic refreshment in one of the racecourse bars.

John Hanmer
From what I remember it was just the two of us, and I'm pretty sure we had a couple of bottles of fizz. We wouldn't have had just one.

Drinking like that never really affected me. You do soon sober up as well. When I first joined the press room in 1960 the drinking that went on in press rooms before racing was absolutely fantastic. There was almost always a bottle of whisky put in the press room and it had almost always all gone before the first race. The last time I went racing was to Stratford about seven years ago. Nobody was drinking – I just had a cup of coffee.

Also on the BBC team that day was Sue Barker, main presenter of the Ascot coverage on Grandstand, which was scheduled to show the first four races.

Sue Barker
I had already worked quite a lot with Frankie and he was always such a wonderful guy to interview. I remember interviewing him at the start of the day. He told me he thought he had a really good book of rides and that he was confident of having at least three winners.

One down, six to go: Wall Street beats Salmon Ladder in the Cumberland Lodge Stakes at Ascot in 1996 to kick of Frankie Dettori's Magnificent SevenCredit: Sporting Life/Dan Abraham

Dettori's confidence was justified. He made all to claim the opening Cumberland Lodge Stakes on the Saeed bin Suroor-trained Wall Street. That was a win he expected. He was not similarly bullish about stablemate Diffident, yet he held on to land the Diadem Stakes by a short head from the fast-finishing Lucayan Prince, a sprinter he would have partnered but for being required on Diffident.

John Hanmer
Walter Swinburn should have won that race by a minute on Lucayan Prince. The horse was absolutely running all over them but he kept getting into trouble and just got done. Had he won it would have scuppered the whole day.

The hat-trick was completed when Mark Of Esteem, another Bin Suroor-trained Godolphin squad member, took the card's Group 1 highlight, with Pat Eddery beaten into second on Bosra Sham. Had Dettori stopped there, it might have been Mark Of Esteem who made the biggest headlines. He was not for stopping and then took the 26-runner Festival Handicap on 7-1 topweight Decorated Hero for John Gosden.

Dave Currie, Dettori's valet
It was all amazing, even more so because my dad, Frank Currie, had been Alec Russell's valet when he rode his six-timer at Bogside. Frankie was like a son to me. As the day went on, and one went to two, two went to three and three went to four, you started to think: 'Hang on, what's happening here?'

Frankie Dettori makes it four for the day on Decorated HeroCredit: Phil Smith

Nick Cheyne, Ascot clerk of the course
A real sense of excitement started building when he won on Decorated Hero. I remember more and more people rushing after every race to get to the old winner's enclosure, which didn't have much in the way of tiered viewing.

Racing's section in Grandstand was now over. However, editor Dave Gordon agreed to keep the lines open for the recording of the subsequent three contests, just in case Dettori continued his hot streak. Hanmer invariably called races that were not being televised live, and did so again as Dettori and Bin Suroor took the Rosemary Stakes with Fatefully, backed down to 7-4 favouritism.

Hanmer was again in action when the record button was pressed for race six, the Blue Seal Stakes, at 5.00. The bosses at BBC Radio 5 Live had decided the event should be transmitted live, which broke two normal rules: one, the reading of the classified football results was delayed; two, commentator Peter Bromley consented to hang around for a spot of unpaid overtime. He did this begrudgingly. His mood changed for the better when Dettori and Ian Balding successfully joined forces with Lochangel.

Bookmakers on and off the course faced paying out enormous sums to punters who, like Yates, had combined Dettori's horses in multiple bets. For that reason, his mount in the concluding Gordon Carter Handicap, the Sir Michael Stoute-trained Fujiyama Crest, opened up at around 7-2 having been four times that price in the morning. The man about to ride him was even more ebullient than usual, particularly when told by the BBC's Julian Wilson that Arsenal had just won. "Don't touch me because I'm red-hot," he told Wilson, making a sizzling noise. Wilson responded, telling him: "Frankie, go out and do it."

Frankie Dettori celebrates alongside Fujiyama Crest in Ascot's winner's enclosureCredit: Mark Cranham (racingpost.com/photos)

Mike Dillon, director of public relations for Ladbrokes
I was in regular contact with our trading director Colin Miles. He could see the tsunami happening, so we started sending money to the track, trying to shorten Frankie's horses.

During the morning, Fujiyama Crest had been friendless at 12-1 and 14-1, but in the minutes before the race he was being backed at 2-1. It was the most bizarre thing you could imagine.

The problem was bookmakers couldn't shorten him any further because guys like Gary Wiltshire thought this was the chance of a lifetime.

Gary Wiltshire
Believe it or not, I was in front after five races. I did a few quid in the sixth, but it was nothing to worry about. I knew we were going to get it all back and more because Frankie's horse in the last was certain to start at a ridiculous price.

It's 25 years ago but it feels like 25 minutes ago. I remember everything. The first bet I laid was £40,000 at 7-2 with Coral. All the offices smashed into him but I didn't take one public pound on that horse. It was all trade money. With all the bets added together, I had him as a £1.4 million loser.

The problem was I got carried away. In every fat person there's a thin person trying to get out – and this all happened before I had my gastric sleeve operation. I was like the comedian at the end of the pier.

Gary Wiltshire: lost £1.4 million but found fame as a result of the Magnificent SevenCredit: Steve Nash

In his head, Wiltshire can still hear the sound of the bell that rang as Fujiyama Crest, winner of the same handicap 12 months earlier, led the field into the home straight having made all to that point. Eddery, who had also chased Dettori home in the Blue Seal, mounted a fierce challenge on Northern Fleet, the two horses soon clear of their rivals. Eddery inched closer and closer but for Dettori, his fans and his sport, the winning post came in time.

"Fujiyama Crest finding a bit more . . . and it's seven for Frankie!" said Hanmer in his commentary on a race that was without O'Sullevan, who had headed to the BBC's private box to meet director general John Birt.

Sir Peter O'Sullevan (from his 2014 autobiography)
Every able-bodied man in the BBC scanner-van was dispatched to find PO'S so that he could call the final races on this historic occasion. Not one thought of looking in BBC hospitality, so it was my estimable colleague John Hanmer who called Frankie's fifth, sixth and seventh victories.

John Hanmer and Frankie Dettori, pictured at the 20th anniversary celebration of his Magnificent SevenCredit: Edward Whitaker

John Hanmer
I don't think Peter had any intention of calling the Fujiyama Crest race. He hated doing races after we came off air. He was meticulous in his preparation and would never have wanted to do a race for which he hadn't properly prepared.

My one desire was not to make a balls-up. I don't think my commentary on the race was sensationally good but I also don't think it was sensationally bad. At the time I was quite pleased to have done the race but it's now a long time ago. The novelty soon wears off.

Richard Hughes, rider of seventh-placed Pearl Venture
As we turned for home Frankie was in front but he was off the bridle, with plenty of us queuing up behind him. Pat Eddery and I were cantering. Pat turned to me and said: "He won't win this one!" He did win though, and it was unbelievable. Frankie and his confidence definitely got the horse over the line.

Dave Currie
A lot of jockeys who weren't riding in the last and would normally have gone home were still in the weighing room. We were all wondering, 'Could this really happen?'

Everybody was glued to the TVs because we all knew there was a chance history was about to be made. One or two of the lads were actually shouting for Pat, but that sort of thing happens in all sports.

Frankie Dettori pushes Fujiyama Crest to victory to bring up his Magnificent Seven at Ascot 20 years ago

Ascot went wild, although only those at the track, watching in betting shops or listening to BBC Radio were able to enjoy Dettori's tour de force live. Grandstand had finished at 5.20pm and the controllers of BBC1 refused to extend the programme. As such, at 5.36pm, when Fujiyama Crest burst out of the stalls, BBC1 viewers were one minute into a repeat of Dad's Army. It was the episode in which Captain Mainwaring's staff car breaks down when Private Pike borrows it to take his girlfriend to the pictures.

Sue Barker
I only worked up to the end of the fourth race but I decided I just couldn't leave. I stayed around at Ascot as a fan. The atmosphere kept building, building, building. It was truly magical. I wasn't even aware the BBC didn't do the final race live. Maybe they just thought Fuji wasn't going to do it?

That final race will live long in my memory as one of the great sporting moments. I went right down to the rails. I've never heard noise on a racecourse like there was when Fuji was coming up that straight. We knew we were witnessing something incredibly special. Thinking how special it was still gives me goosebumps. It was such a great advert for racing.

Sue Barker was presenting the BBC's Ascot coverage on September 28, 1996Credit: Clive Brunskill

Nick Cheyne
I remember Frankie being presented with a magnum of champagne that he sprayed around enthusiastically. It's probably the first and only time there has ever been a Formula One moment at Ascot.

Dave Currie
It was absolutely unbelievable. When he got back to the weighing room the champagne was flowing and Frankie was going crazy. What he said is probably unprintable! It was all so unreal.

Up in Morecambe, Darren Yates was having a rollercoaster afternoon. His team were beaten 4-1 at home. On the other hand, he won £550,823.54.

Darren Yates
I watched the last race in a little local bookies called Pauline's. When Frankie won I felt numb. I asked Pauline to work out my winnings. She told me it was £250,000. I asked if that included the £1 each-way acca, which she had missed because it was added at the bottom of the slip. "Jesus," she said. "That's another £300,000."

I got a call from William Hill's Graham Sharpe at about 7pm. "You've had a good day," he said, and then explained that although we had won £550,000, their limit was £500,000. He said he wanted to fly my wife and me to London to do some PR work. He said if we did that he thought they would give us the extra £50,000. I didn't spend too much time thinking about whether to say yes.

Frankie Dettori with Fujiyama Crest, who lived with the jockey in Newmarket after completing his Magnificent SevenCredit: Edward Whitaker

Dettori had become a media sensation, his Magnificent Seven leading the Saturday evening news bulletins. Everybody wanted him, including Top of the Pops, which he presented two months later. It had been a lucrative day for the world's most famous jockey, who later adopted Fujiyama Crest as a family pet. The experience was less obviously positive for bookmakers, particularly Wiltshire, who suddenly owed £1.4m. It took him four years, and required him to sell his house, but he paid off his debts.

Mike Dillon
In those days betting shop systems weren't as efficient as they are now, so bookmakers didn't realise how much the Magnificent Seven had cost until the early part of the following week. It was an ever-moving landscape and the cost kept getting higher and higher.

Unlike those who were weeping, I thought it was the best day the bookmaking industry had ever had. Racing was catapulted on to the front pages and the following Saturday everybody was doing Dettori multiple bets. I joked in the office they should have moved the cost of the Magnificent Seven from the trading budget to the marketing budget.

No hard feelings: Mike Dillon of Ladbrokes shakes Frankie Dettori warmly by the throat on the 20th anniversary of the Magnificent SevenCredit: Edward Whitaker

Gary Wiltshire
When he won that last race all I really felt was shock. It was like someone was hitting me over the head with a hammer. When that happens you don't feel the pain straight away. You feel it when you wake up in the hospital bed.

Would I do it again? No. I thought I was being clever, laying a horse who should have been 20-1 at 2-1. In the end I wasn't clever because Frankie won.

I still went to Milton Keynes dogs that night. When I got to there my son Nicky, who was doing the pitch for me, said: "Dad, we've had a bad start. We've done £17 on the first race." I thought to myself: "Little do you know." To be fair, we did make £300 profit that night.

Looking back, I still say that day at Ascot was the best I've had. It was fantastic for me. I've lived off it for 25 years. I started doing the betting on the BBC and also began working for Sky. Frankie did me a favour. Mind you, I would love to have my house back.

This article was originally published for Members' Club Ultimate subscribers. Members can read more articles by award-winning writer Lee Mottershead here:

Leonna Mayor: 'People have no idea what my life has been like – I've no reason to be ashamed'

Jamie Spencer: 'If you don't like the way I ride, don't bet on me or don't book me for a ride'

'I'm terrified of the future, I may have to move abroad to do this job' – what next for pro punters?

The betting ring: punters v bookies – what life was really like inside John McCririck's jungle

The digital age: how Betfair created a new generation of punters – not all of them well-informed

The Front Runner is our latest email newsletter available exclusively to Members' Club Ultimate subscribers. Chris Cook, a three-time Racing Reporter of the Year award winner, provides his take on the day's biggest stories and tips for the upcoming racing every morning from Monday to Friday