When the great Jim Clark was killed in a minor Formula 2 race at Hockenheim in Germany in 1968, the world mourned a genuine sporting icon.
The thing with Clark’s death however, was the feeling among his peers that if the Scot could be killed in a racing car — even at a time when motor racing tragedies were an almost weekly occurrence — that the rest of them had no probability of long-term survival.
Clark’s death was, as then Ferrari driver Chris Amon later recounted to F1 scribe Nigel Roebuck, almost beyond comprehension.
“As well as the grief, there was another dimension altogether,” Amon recalled. “If it could happen to him, what chance did the rest of us have? I think we all felt that. It seemed like we lost our leader…”
And so it was at 2.17pm that day at Imola when Ayrton Senna crashed at the Tamburello Corner.
The unthinkable had happened and when the news filtered through later that he had died, it was almost inconceivable.
And not just to his driver colleagues, but also to the public at large.
Perhaps the greatest driver of his generation — almost certainly the quickest, if not the most successful of his era — was killed in action in a Grand Prix.
This was incomprehensible.
Sure, safety in the sport had improved radically down the years, thanks mainly to the efforts of Jackie Stewart, but seeing a driver — any driver, not to mention one of the Brazilian’s calibre — dying at the wheel of his car was not something that had been witnessed since the tragic demise of Riccardo Paletti in Montreal in 1982, some 186 grand prixs previously.
Watching the events at Imola from a space a long way away on television, like millions more, I saw Ayrton Senna’s Williams FW16 fail to take the 300kph Tamburello left-hand sweeper and instead career into the outside retaining wall at seemingly undiminished pace.
The car disintegrated into the many parts it was safely supposed to. Unfortunately one of those disintegrating bits killed him.
I was not a big Senna fan. I thought him to be quick, but at times unhinged.
The famous championship decider in Suzuka when he won the title by the simple expedient of taking main rival Alain Prost off at the first corner did not sit comfortably.
Indeed his career-defining speed — 61 pole positions gave a clear picture of his uncanny ability to drag a banzai lap out of even the most recalcitrant car — was always blunted by his apparent willingness to put opponents into the wall.
Prost himself came very close to tragedy at Senna’s hand.
In the Portuguese GP of 1988 the two were hurtling down the main straight at some 320kph when Senna, on the outside, made a lunge at the Frenchman which nearly forced him into the Estoril pit wall.
The Frenchman, known as ‘the Professor’ for his studious approach to his craft, later reflected:
Suzuka, where the two would later clash in two separate title-deciding accidents — was still down the road.
The dichotomy of views of his greatness has heightened since Senna’s tragic and in many ways unnecessary death.
Some say he died a tortured man. Deep faith and a deep charitable pocket hid a desire to win which often defied belief, particularly for a man whose bible-reading occupied most hours on a long-haul.
An early divorce — his wife would not come to Britain to live because it was too cold, so she was dispensed with — led a shy, but confident young man from Brazil to the centre of racing.
Predecessors such as the Fittipaldi brothers, the tragic Carlos Pace, and Nelson Piquet fuelled the ambitions of the young Sao Paulan.
And a whole lot more with him.
Roberto Moreno, Chico Serra, Mauricio Gugelmin, and Raul Boesel, among others of the era had made the trip to find fame as racing drivers.
Each had success. None had Senna’s grit, determination, single-mindedness, or talent. Another Brazilian talent he would nurture — Rubens Barrichello — later played a big part in what was Senna’s tragic weekend.
Indeed, from the outset of the meeting, there was an air of desperation hanging over Senna and Imola.
Having just joined the championship-winning Williams team from McLaren, where he had won his three titles, Senna had been beaten fair and square in his home race in Brazil by new-boy Michael Schumacher’s Benetton.
And then at the second race, the Pacific GP at Aida in Japan, he was involved in a first-corner collision with Mika Hakkinen and Nicola Larini. Schumacher won again.
Despite unsettling rumours that Benetton’s pace was as a result of an illegal car, Senna was unhappy with Williams’ 1994 contender, the FW16.
The previous year’s title-winning car has been shorn of the recently banned electronic aids when Senna arrived and he was never happy with the car in pre- season testing.
Twenty points behind Schumacher after just two races, he was under pressure to produce and determined to lay down a marker at Imola.
But in Friday practice, his protégé and Jordan driver Barrichello was involved in a terrifying 230kph accident at the Variante Bassa chicane and was knocked unconscious.
When he awoke in the medical centre, the first thing he saw was Senna standing over his bed.
Then, 18 minutes into final qualifying on Saturday afternoon, Austrian Roland Ratzenberger’s Simtek speared off the road at the Villeneuve curve at some 314kph and into the concrete retaining wall at undiminished speed.
He was killed instantly.
Senna commandeered a course car to go to the scene, only to be told by the late F1 medical officer and world-renowned neurosurgeon Dr Sid Watkins there was no hope for the Austrian.
Senna broke down in tears and Watkins, who was a close friend, told him he should retire immediately and go fishing with him at his Scottish estate.
Watkins would later write that he had had a premonition Imola would be a bad weekend.
“I’d been pretty upset after Ratzenberger was killed. But by the Sunday morning I had settled down. I can’t say I was looking forward to the race, but I was certainly looking forward to the end of the weekend.”
Senna was fastest in the Sunday morning warm-up by nearly a second, so his speed was certainly not been dented by the incidents of the previous two days.
In the drivers’ briefing before the race however, a minute’s silence was held in memory of Ratzenberger.
Watkins, who was at the meeting, reported later he did not think it had been a good idea.
“When I looked around the room most of the drivers were taking it well, except for Ayrton who, for the second time in 24 hours, was crying.
"He was doing his best to overcome his grief, but silent tears were running down his face and he was licking them away to conceal his distress,” he later wrote.
Despite everything, Senna started from pole position in Sunday’s race, but at the race start there was another unsettling incident when Pedro Lamy’s Lotus rammed the back of JJ Letho’s stricken Benetton, scattering
debris all over the start straight and injuring some spectators.
The race was not stopped and a pace car was called out to lead the field around while the wreckage was cleared.
On lap six, the pace car pulled into the pits and racing resumed with Senna leading Schumacher, and Gerhard Berger’s Ferrari in third.
Watkins, sitting in the medical car with his driver Mario Casoni as the field was unleashed once more, got the chills.
“Senna and Schumacher went off like lightning on their next lap. My premonition crystallised. I turned to Casoni. ‘There’s going to be a fucking awful accident any minute.’”
Seconds later the red flags signifying the race had been stopped were flying. Watkins says he knew immediately something had happened Senna.
When the medical car got to Tamburello, Ayrton was slumped in his cockpit.
“For the third time that weekend there was a frantic effort to cut the chin strap and get the helmet off. We supported Ayrton’s neck and removed the helmet.
"His eyes were closed and he was deeply unconscious. He looked serene. I raised his eyelids and it was clear from his pupils he had had a massive brain injury.
"We lifted him from the cockpit and laid him on the ground. As we did he sighed and, though I am totally agnostic, I felt his soul departed at that moment.”
Senna was transferred by helicopter to the Maggiore Hospital in nearby Bologna. He still had a pulse, but Watkins says he knew then the driver could not survive.
The helicopter arrived at the hospital at 3pm.
At 3.10pm, his heart stopped but was restarted and he was placed on a life-support machine.
His heart stopped again shortly after a priest gave him the last rites at 6.15pm. His death was formally reported at 6.40pm.
To this day racing cognoscenti still argue about who was the greatest F1 driver of all time.
Was it Fangio, Clark, Stewart, Villeneuve, Prost, Schumacher, or Senna?
Whatever their conclusion there is no doubt the Brazilian was an all-time Grand Prix great.
The sadness is that Senna’s death was entirely avoidable and the safety measures implemented after his demise meant there were no further fatalities in the sport over the next 20 years until Jules Bianchi died in Japan in 2015.
Senna’s historical legacy as one of the greatest drivers to walk the planet will live forever and is best summed up by his great rival Alain Prost.
“Ayrton was the best driver that I ever competed against. He was the best because he was different. It was almost frightening the way he was able to impose himself on everyone.
“He was able to get something more from the team and the people working with us.
"With Ayrton, it was not just what he did on the track; he had this concentration and focus on using the full potential of the car, the tyres, everything.
“He was the best. No question.”
Few motor racing deaths have proved as controversial as that of Ayrton Senna at Imola on May 1, 1994.
While his shocking passing provoked a worldwide outpouring of grief – almost three million people turned out for his funeral in Brazil alone – it also sparked lengthy and contentious 13-year period of trials, tribunals, and appeals.
And still, nobody is 100% certain what exactly happened before the moment of impact on that afternoon a quarter of a century ago.
What we do know – from the official autopsy results – is that Ayrton Senna Da Silva died as a result of ‘multiple fractures at the base of the cranium, crushing the forehead and rupturing the temporal artery with haemorrhage in the respiratory passages.’
There were ongoing rows among medics as to whether he died instantaneously or later at the hospital.
The fact is that he was kept alive byartificial means for several hours until he was finally declared dead.
Estimates of the forces involved in Senna’s death suggest a rate of deceleration equivalent to a 30-metre drop, landing head-first.
Frank Dernie, a veteran F1 designer and aerodynamicist who worked for many teams over the years, including Williams, says that when the FW16 hit the wall at Tamburello, the right front wheel was trapped between the wall and the car’s chassis.
“As the suspension collapsed and as the car skidded along the wall, the wheel popped up and hit him on the head. If it was not for that, he would have been uninjured,” Dernie maintains.
Unfortunately for the driver, when the wheel hit him, various bits of the suspension were still attached to it.
The force of the wheel’s impact with his head caused skull fractures.
On top of that, a piece of the suspension upright assembly still attached to the wheel penetrated his Bell M3 helmet just above the right eye.
So, we know what killed him, but we still do not know why he ended up in that Tamburello wall.
Many theories have been put forward, even if the Italian Supreme Court of Cassation ruled in April 2007 that the accident “was caused by a steering column failure.”
Many others - Dernie included - believe that because of the accident at the start of the race and the subsequent time cars spent behind the pace car that tyre pressures had reduced by as much as 20%.
This meant that movement within the tyres was up by four to five millimetres.
Dernie says this meant the car was bottoming out over the bumps at Tamburello and effectively sliding on the metal skid plate under the chassis.
The effect would be similar to a car aquaplaning in wet conditions, giving Senna no control over the steering.
Many of Senna’s fellow drivers and team owners are certain, however, the accident had to be caused by mechanical failure.
Gerhard Berger, the Ferrari driver who was running third in the race behind Senna, says when he saw the Williams hit the wall “it was very clear to me it must be a technical problem.
Martin Brundle, the former driver turned Sky Sports F1 commentator recalled: “I think maybe the car was a bit too low and he hit the ground.
"The film of the lap before seemed to show the car was handling well and that the tyre pressures and temperatures were coming up. That surprised me.
“I spoke to Damon Hill (Senna’s Williams team-mate) about it and he said: ‘Look if the steering broke you’d have seen his hands going like that [indicates a cross-hands movement] but they didn’t.’
"Damon didn’t feel that was what happened. We can only discuss what we know and I don’t know enough to say for certain what happened.
"If you ask me to guess, I think the car was running very low and he hit the ground.”
Ron Dennis, Senna’s former boss at McLaren, is definite the accident was caused by problems with the car.
“The simple fact is that Ayrton almost certainly suffered a car failure. Some say his pursuit of Michael Schumacher [in the title race] was overly aggressive because of his necessity to compensate for the inadequacies of his car, but that is nonsense. That’s just people trying to re-write the script.”
“For sure,” says Alain Prost unequivocally, “it was a mechanical problem.”
Even 25 years on, we still don’t know for certain.
1984 Monaco Grand Prix
The race where Senna announced himself as a star. In torrid conditions on the Monte Carlo street circuit, a number of top drivers including Nigel Mansell and Niki Lauda spun out.
But rookie Senna, in his under-powered Toleman, rose to the occasion, carving his way through the field, having started from 13th, before assuming second on lap 19.
Leader Alain Prost gesticulated for the race to be cancelled, and — just as Senna was about to challenge the Frenchman — Prost got his wish.
Senna would be denied a maiden win, but he had made his mark.
1985 Portuguese Grand Prix
In April of the following campaign, Senna, racing in only his 16th grand prix, took pole for his new Lotus team before a remarkable drive in the wet would see him claim his first of 41 victories.
Senna delivered an error-free performance to win by more than a minute, lapping the field up to second.
1989 Japanese Grand Prix
Senna’s rivalry with Prost is probably the biggest the sport has known.
Their relationship as McLaren team-mates had soured by the penultimate race of the 1989 season, and sensationally boiled over when they collided.
Senna dived underneath Prost at the chicane in a bid to keep his title hopes alive.
Prost knew he would be crowned champion if Senna did not finish and the pair crashed.
Prost retired but Senna recovered to win, only to be disqualified after he was adjudged to have rejoined the track illegally.
1990 Japanese Grand Prix
One year later, and in a reverse of the previous season, Prost, now racing for Ferrari, had to win to take the title fight to the final race in Adelaide.
Senna took pole but his request that it be moved on to the clean side of the track was denied.
Prost claimed the lead on the dash to the right-handed opening bend before Senna deliberately rammed into the Frenchman at high speed, with both drivers ending up in the gravel and out of the race.
1993 European Grand Prix
Senna’s opening lap at a rain-soaked Donington Park is regarded as the finest in the sport’s history.
The Brazilian started fourth but he assumed the lead from Prost within a handful of corners.
In the changeable conditions, Senna put on a masterful display to win.