It was one of the most iconic events in the sport's history, a moment that changed F1 forever, now Adrian Newey reveals how the death of Ayrton Senna at Imola in 1994 affected him.

It was a weekend that the sport will never forget. Still reeling following the death of Roland Ratzenberger during qualifying for the San Marino Grand Prix, fans around the world looked on in horror as Ayrton Senna's Williams suddenly veered to the right and crashed into the barriers at Tamburello on the sixth lap.

The crash was to impact the sport in many ways, not only in terms of safety but also in terms of the cash the sport generated, it was a pivotal moment in Formula One.

Watching the incident from the pitwall was the man who designed the car in which the legendary Brazilian perished, a man who had already designed championship winning cars for Williams and who was to enjoy further success with McLaren and Red Bull.

"The little hair I had all fell out in the aftermath. So it changed me physically," he tells the Guardian, sixteen years on from that momentous day. "It was dreadful. Both Patrick Head and myself separately asked ourselves whether we wanted to continue in racing. Did we want to be involved in a sport where people can die in something we've created? Secondly, was the accident caused by something that broke through poor or negligent design? And then the court case started."

Head and Newey were both charged with manslaughter following the accident. "The court case was a depressing annoyance, and extra pressure," he admits, "but it did not make me question whether I wanted to be involved in F1. It's the self-searching rather than the accusations that really matter."

Asked if he considered walking away from the sport, the Englishman admits that he did. "For the whole team it was incredibly difficult. I remember the day after the race was a bank holiday Monday and some of us came in to try and trawl though the data and work out what happened. They were dark weeks."

As for when he finally managed to absolve himself of culpability, Newey admits: "The honest truth is that no one will ever know exactly what happened. There's no doubt that the steering column failed and the big question was whether it failed in the accident or did it cause the accident? It had fatigue cracks in it and it would have failed at some point. There is no question that its design was very poor. However, all the evidence suggests the car did not go off the track as a result of steering column failure."

When asked, after all these years, he is any closer to knowing the true cause of the accident, he admits; "the right rear tyre probably picked up a puncture from debris on the track. If I was pushed into picking out a single most likely cause, that would be it."

As race fans in Britain eagerly await the release of the much praised film about the legendary Brazilian, Newey is asked if he has already seen it. "No," he replies, "it would not be an easy thing to do."