His Formula 1 career produced an unprecedented level of success – but also a tremendous amount of pain.
By the time Sir Jackie Stewart ended his racing career in 1973 he had won more races than anybody else had ever managed. A record of 27 wins and 43 podiums from 99 starts helped the petrolhead from Dunbartonshire to three world championships before he quit the sport.
Why retire then? Put simply, the risk of carrying on was too great. Motorsport remains a dangerous pastime today even despite the abundance of safety measures in place – back in Stewart's day, every driver really was risking their life whenever they clambered into their cars.
" In those days the number of fatalities was huge, it was ridiculous," the 83-year-old told Mirror Sport. " The race tracks themselves had never been changed since before the Second World War. No run-off areas, nothing.
"The cockpits of our cars meant we were sitting on our fuel tanks the whole time, right down to your knees. It was a different world, but we didn't know any better. Even then, Formula 1 was the fastest technology in the world, but it was very dangerous."
Of course, Stewart survived his career, but not without some close calls. One of the crashes which remains vivid in his memory was at the 1966 Belgian Grand Prix – it proved to be something of a watershed moment, encouraging the Scot to advocate for more safety measures to be taken in a sport which was, at the time, hopelessly devoid of them.
" I had a big shunt at Spa, because the race track was ridiculously unprotected," he recalled. " I knocked down a telegraph pole and went into a woodcutter's hut. I ended up trapped in a farmyard. [Fellow drivers] Graham Hill and Bob Bondurant got me out of the car and it took them 30 minutes – there were no marshals at all.
"I was soaked in fuel. I got Graham to take all my clothes off because I was going in and out of consciousness and I was burning. It was a much higher octane fuel than today. Then, I was lying naked on the floor while they tried to get some marshals, ambulances and there was nothing. They had to get tools from spectators' cars to get me out,
"The medical centre was ridiculous, cigarette ends on the floor. After that, I had a specialist who was good at resuscitation as well as everything else. He came to every race I went to." And that was not the only change he made – in the following years he organised driver boycotts of races at Spa and Germany's Nurburgring in the push to improve safety.
He managed to achieve it, but at some personal cost. Stewart said: "I was very unpopular because of it – I got death threats. People were coming to my house and banging on the doors. We had a big gate we had to fill in to make sure people couldn't get through.
"For a lot of people it was because: 'Motor racing is dangerous, so why aren't you racing?' Our death rate was horrendous and, in a major accident, you never stopped. You drove through the flames. With Piers Courage's accident, I knew it was him because his helmet had come off and it was on the side of the track.
"It was a very big thing against me personally, as president of the GPDA at the time. But it was the right thing to do and it changed the whole element of motor racing safety in my period. I'm proud of that."
Despite his efforts and the progress made on safety features, the fatalities continued. Jochen Rindt died in a crash during practice at the 1970 Italian Grand Prix – the same year he became the first and only racer to posthumously win the world championship. The crash which killed the Austrian was the only one which, by Stewart's own admission, elicited an outwardly emotional response from the Scot.
After declaring he "absolutely" feels lucky to have survived his own racing career, Stewart said: "Death was so close and so often. And we saw it in the worst circumstances. At Monza, when Jochen died, I wasn't at the accident, I was in the pits at the time.
"But I was told he had an accident and I went to see [Rindt's wife] Nina and I said: 'I'll go see him and find out, don't worry about it'. I did go to see him but he had already died. He was in the back of a truck, a trailer, with no cover over him.
"In Italy, nobody was allowed to die at a race track because if they did, the whole weekend had to stop – that was the law. So Jochen died 'en-route to hospital', the same as [Ayrton] Senna. But they were dead.
"I went back and Ken [Tyrrell] said: 'Right Jackie, you've got to go out and qualify'. I went out and I burst into tears getting into the car – I'm not emotional normally – and then I went out and put in the fastest lap I ever put in at Monza.
"I put myself on the front row, second fastest to [Clay] Regazzoni's Ferrari, and I came back in after four laps and burst into tears again getting out of the car. It was the only time it ever affected me, because I had never gone to the driver before and he was a really good friend."
How can someone who saw so many of his friends and fellow drivers die while racing have only been affected by one of them? "I learned to manage emotion," he responded simply. "I can't think of anybody I know who's been to more funerals than I have, but it was an important thing to do. Francois Cevert, for example, would never go to a funeral – he was frightened of them. It was a very tough time."
The Frenchman, Cevert, was a great friend of Stewart. But he was another who lost his life in a crash – it was that incident which led to Stewart never taking to the start line for what was due to be his 100th and final Grand Prix.
Despite all the tragedy, many of his memories of his racing days are much more positive. He recalled the great friendships he had with obvious enthusiasm and wore a smile on his face when reminiscing about an era of the sport which is barely recognisable compared to today.
Stewart said: "The camaraderie was fantastic – we all travelled together. Nowadays, everybody has helicopters and private plans waiting for them and they have their motorhomes today where they've got a shower room and a massage room. In those days, we were in the back of the truck!
"But the camaraderie was really close. The girls, Helen was doing the land charting and the timekeeping for the team. That was what all the wives and girlfriends did, it was part and parcel of the business. That created the Doghouse Club, where all the girls could go between practice and the race, so all the girls were friends as well as the drivers. It's different today.
"And of course we were driving GT cars, Can-Am cars, IndyCars, Touring cars – you drove everything to make some money, because it was small in comparison to today, very small. I did 69 crossings of the Atlantic one year because of IndyCar and doing television in America and so forth, as well as still racing.
"The whole thing was different. In 1971 I made £1m for the first time in a season. What do [Max] Verstappen and Lewis [Hamilton] make now? Huge money! And that's good, I'm glad. By the end I was making good money too. Times have changed."
All of those friendships, successes and heartbreaks make up a new documentary from Sky. STEWART, a film executive produced by the racing legend's son Mark, begins with him as a youngster driving his Austin A30 in the Scottish Highlands – the car he bought with the money he earned serving petrol at the local garage.
From there it takes in his racing career, his marriage to his devoted and beloved wife Helen and the severe dyslexia which left him unable to read and write – even when driving to his world championships.
"When you see it, take a hanky with you," Stewart advised Mirror Sport. "Prince Albert came to the first viewing of it in Monaco and he sat on one side of me and [F1 chief executive] Stefano Domenicali was on the other. Both of them were in tears.
"I don't know anyone who's seen it who hasn't had a weep. It's been beautifully done. I think it will be the best motor racing film ever made – and I had nothing to do with it! I didn't even know it was being made, to begin with. It was finished, almost, before I knew."
STEWART will be shown on Sky documentaries and streaming service NOW on December 30.
