Ayrton Senna: Mahatma Gandhi, Mother Theresa, Dalai Lama, Nelson Mandela and Senna - how a racing diver gained near demigod status to the people of Brazil

Three million people turned out on the streets of Sao Paolo for Senna's funeral after his tragic death at the 1994 San Marino Grand Prix

There are very few people to have walked this earth and commanded almost demigod status attained by Ayrton Senna.

Perhaps it is sacrilege to state that of any human being, especially a sportsman - for that is all he ultimately was.

But to the Brazilian people, Senna was their Mahatma Gandhi, their Mother Theresa, their Dalai Lama, their Nelson Mandela.

Senna was not a saviour of souls, a healer of the sick, a champion of civil rights like those mentioned, but he offered up hope, and was an inspiration to a nation for whom the overwhelming majority, in their slums and favelas, could only dare to dream of emulating their hero.

On the day he died - May 1, 1994 - and for those that followed until his funeral four days later, that nation grieved for a sportsman on a scale never seen before or witnessed since.

On the day Senna's body was flown back to his home city of Sao Paulo on May 4, an estimated three million people lined the streets to pay their last respects as it made a 20-mile journey from the airport to the July 9 Palace where he lay in state.

That in itself tells you all need to know about the esteem in which Senna was held, that he should be treated as if he were royalty or a president.

Twenty years on and Senna is still vividly remembered. But why? Why do we not do the same for Juan Manuel Fangio, Alberto Ascari, Graham Hill or Jim Clark, all multiple Formula One world champions?

The manner in which Senna's life was cruelly cut short, at the age of 34 and with arguably at least one more world title to be won, plays a distinctive part.

Fangio died in hospital at the age of 84; Ascari was killed in an accident during a private practice session at Monza, himself young at 36; Clark, even younger at 32, in an F2 race at Hockenheim, whilst Hill died in a plane crash, aged 46.

None of those, however, were in the public spotlight like Senna as the blackest weekend in F1's history played out to millions around the world at the San Marino Grand Prix at Imola.

Read more: Remembering Roland Ratzenberger - Imola's forgotten tragedy
Senna's genius captured a generation who never had the privilege of seeing him

On Friday, fellow Brazilian Rubens Barrichello suffered a sickening crash from which he was fortunate to escape with only minor injuries.

On Saturday, Senna watched on a television screen as Austrian Roland Ratzenberger was killed when his Simtek smashed into a wall following a front-wing failure.

Senna later cried on the shoulder of close friend, the late Professor Sid Watkins, then the FIA's medical delegate, who urged him to retire and go fishing. If only he had listened.

Even at the start of the race itself there was an incident involving JJ Lehto and Pedro Lamy, the flying debris from which injured nine spectators.

And then there was Senna's accident, just three races after starting a new chapter in his career with Williams, the cause of which has never been determined even after all these years.

It is widely known the steering column broke as Senna headed into the Tamburello Curve at 190 miles per hour, and although human instinct resulted in him hitting the brakes hard, the impact into the concrete barrier was measured at 130mph.

Three years ago Adrian Newey, Williams' design engineer at the time of Senna's death, suggested a right-rear tyre puncture due to on-track debris was the most likely trigger for the accident.

An autopsy concluded that cause of death was "from a blow to the head from a blunt object", above the right eyebrow, with experts believing it to be the front suspension with the wheel still attached.

What many people recall from the accident are the camera shots from a helicopter hovering above; Senna's head moving fractionally, offering hope he was still alive, before being attended to by Watkins and a number of marshals.

Their efforts were effectively in vain as the blow to the brain was so severe it is understood to have killed Senna instantly, even though his heart and lungs still functioned via a life-support machine until turned off over four hours after the crash.

Part of Senna's mystique was his devotion and connection to God, his religious beliefs, his quest to seek answers in the Bible, which many of a secular persuasion could not understand.

One of Senna's oft-repeated quotes is the line "If you have God on your side, everything becomes clear".

This goes to the very essence of the man himself as Senna was known to often discuss the meaning of life, as revealed by Ron Dennis who, as team principal of McLaren, helped him win his three world titles.

As a devout Catholic, and from a nation for whom Catholicism is part of their way of life, not an addendum to it, this struck at the heart of the Brazilian people, further elevating Senna up to a different plateau in their eyes.

Senna's success was one thing, his three championships, 65 poles and 41 victories merely statistics at the end of the day, but allied to his spirituality, he was deemed to therefore transcend most mortals.

On the track, Senna was undoubtedly a genius, his will to win second to none, his desire to push to the limit and then to try to go beyond that almost frightening, underlined by his unnerving rivalry with Alain Prost.

Off it, there was a complexity and a depth to Senna's character that only added to his persona, that has ensured he is remembered to this day.

And then there is his legacy, that tragic weekend at Imola inspiring the sport to seek new and improved levels of safety.

It was Formula One's dangers that intrigued Senna, which is why he was so staunchly against the advent of new technologies that aided a driver.

Senna believed the sport should be pure, nothing more than man and machine in a quest to push the boundaries, which were sadly revealed that fateful weekend in Imola.

Twenty years on, no driver has since been killed at a Formula One event, a lasting epitaph to Senna and his greatness.