A three-time world champion, he led a life of remarkable achievement, on and off the track, in motor racing and in the airline business.

He will always be remembered for the accident at the 1976 German GP that almost claimed his life. His subsequent comeback, overcoming physical and mental challenges to return to the very top of his game, is surely one of the most extraordinary stories in sporting history.

He was also an utterly unique personality, never afraid to say exactly what he thought, and always ready to offer a perceptive insight in any situation.

He coupled that with a wicked sense of fun that belied the outwardly serious and dour image that he had inadvertently fostered in his Ferrari years, when he scored grand prix wins with metronomic precision.

Born Andreas Nikolaus Lauda in Vienna on February 22nd 1949, he grew up in privileged circumstances, with a wealthy paternal grandfather. He showed little interest in formal education, and gravitated instead towards cars. In 1968 he acquired a Mini Cooper, and without the knowledge of his parents he made his competition debut at a hillclimb in April that year, finishing second.

Niki Lauda, March 712M - Cosworth with Dieter Quester, March 712M - BMW Photo by: LAT Images

A subsequent row led to an estrangement from his father, and Lauda was thereafter obliged to make it on his own. He quickly traded up to a Porsche 911, and then moved into Formula Vee in 1969. In 1970 he gained further experience in what was a wild era of F3, his season punctuated by accidents.

In 1971 Lauda bought an F2 seat with March, securing a best result of fourth at Rouen at a time when the field was usually packed with established grand prix drivers. He also made his F1 debut with a year-old March on home ground at the Osterreichring, where he retired after qualifying a humble 21st.

He financed his 1972 F1 season as Ronnie Peterson's teammate at March with a bank loan, confident that he would eventually succeed and be able to repay it. It was a fruitless year with difficult and uncompetitive cars, but he showed signs of progress in F2, taking three podiums and fifth place in the European championship.

However, by the end of the year he was still in debt and out of a drive – and few gave him much chance of ever making it.

He then concluded a deal with Louis Stanley to race for BRM in 1973. It was a typical bold Lauda move – he took another bank loan and promised Stanley he would bring some backing. He knew that the sponsorship would not be forthcoming, but was convinced that he would do so well that he would eventually be paid to drive for the team, which is what actually transpired.

Results were few, but Lauda showed sparks of genuine promise, and he did enough to impress Enzo Ferrari, who duly signed him for 1974. It was to be the start of a remarkable partnership. The team had hit a low in 1973, but Lauda energised Maranello, bringing a new technical focus and forming a close bond with engineer Mauro Forghieri.

Niki Lauda, BRM Photo by: LAT Images

Lauda was well versed technically, and was adept at honing a car. He also took physical preparation to hitherto unseen extremes, kick-starting the modern era of gyms and physios. He was the complete package.

He also showed incredible speed that year, taking nine pole positions, and scoring his first wins in Spain and Holland. However, a string of retirements in the latter part of the season saw him drift out of title contention.

He made amends in 1975. Armed with the iconic 312T, he again took nine poles, but this time five wins and consistent scoring carried him to Ferrari's first world championship since 1964.

He maintained that form into 1976, logging four wins and two second places in the first six races.

However, as the season went on James Hunt and McLaren began to gather momentum, and the battle between their teams became mired in controversy. Despite an escalating on-track rivalry, the two men remained good friends.

Everything changed at the Nurburgring on August 1, when Lauda was pulled from his burning car by his fellow drivers and rushed to Mannheim hospital with burns and lung injuries. He was given the last rites, but through sheer determination and iron will, he pulled through – and from the start his focus was on returning in the cockpit.

Defying the odds, he was back in his 312T2 at Monza just six weeks later, overcoming not just the physical challenges but also the mental side. He would make no secret of the demons he had to overcome to get up to speed.

Niki Lauda, Ferrari 312T2, crash Photo by: LAT Images

He fought valiantly to defend his title over the remaining races of the season, taking an astonishing fourth in Italy, and third place in the USA. In the soaking wet finale at Fuji he pulled into the pits and parked – and made no attempt to disguise the fact that he simply didn't want to carry on in the atrocious conditions. Hunt duly secured the third place he needed to pip Lauda to the title by a single point.

In South Africa early in 1977 in Lauda scored his first win since the accident, adding two more successes and seven other podium finishes on his way to securing his second title by a comfortable margin.

However, there was considerable tension behind the scenes, a result of Ferrari headhunting Carlos Reutemann as his replacement while Lauda was still in hospital. Long before the end of the year he had agreed terms with Bernie Ecclestone to race a Brabham-Alfa in 1978.

Lauda was happy at the British team, enjoying the atmosphere fostered by Ecclestone, designer Gordon Murray and team manager Herbie Blash. The first season brought wins in Sweden (with the controversial fan car) and Monza, but the team lost its way in 1979 as ground effect technology moved on apace.

By the end of that year Lauda, already busy with setting up an airline business, began to question his commitment. After running a few practice laps at the Canadian GP with the new Cosworth-powered BT49, a promising package that should have caught his attention, he'd decided that he'd had enough – and walked away from the sport.

He stayed away through 1980, but by the summer of 1981 he was having second thoughts. Ron Dennis, who ran him in the 1979 BMW Procar series and had by now taken charge of McLaren, kept badgering him about a possible return.

Niki Lauda, McLaren MP4B Ford Photo by: LAT Images

A visit to the Italian GP led to a test in John Barnard's revolutionary carbon MP4 at Donington, and having demonstrated both to the team and himself that he was still quick and still motivated, he signed up for 1982. However, Dennis played hard ball on the money, and the initial contract gave McLaren an option to ditch him if didn't work out.

Lauda soon silenced any doubters, taking a solid fourth in his comeback race in South Africa, and winning third time out on the streets of Long Beach. He would log another victory at Brands Hatch, and take fifth place in the world championship.

The 1983 season proved tougher for Cosworth-equipped McLaren as the swelling ranks of turbo cars began to dominate and finally find reliability. Lauda had pushed Dennis to find a turbo engine, and he helped to broker a deal for Porsche to design and manufacture a V6, to Barnard's specification, and with finance from TAG.

At Lauda's insistence, the engine was readied for an early race debut at that year's Dutch GP, and useful data was gathered by the team in the four races it contested.

Meanwhile, Dennis had an unexpected chance to further strengthen the McLaren package when Alain Prost came on the market after just missing out on the title with Renault at the final race. He was quickly snapped up as Lauda's teammate.

McLaren would enjoy a sublime 1984 season, the TAG engine proving very competitive, especially in race trim, helped by an effective electronics system. The championship developed into a battle between veteran Lauda – he was 35 at the time – and the younger and relentlessly ambitious Prost.

Both men were known for a methodical and technical approach to their racing, and coming to the conclusion that he couldn't beat his teammate in qualifying, Lauda focussed on preparing his car for Sundays. It paid off as he scored five wins and pipped Prost to the title by just half a point at the Estoril finale.

Niki Lauda, McLaren MP4/2 TAG Porsche Photo by: LAT Images

In 1985 Lauda suffered a string of retirements as Prost built up the momentum that would see the Frenchman secure his first title. Lauda meanwhile felt increasingly frustrated in the camp, and his relationship with Dennis began to unravel.

At his home race in August he announced that he was retiring at the end of the season – his only win of 1985, next time out at Zandvoort, gave him huge satisfaction. He briefly led his final F1 race on the streets of Adelaide, only for a brake failure to pitch him into the wall. This time he walked away from the cockpit for good.

Subsequently he was able to devote his energies to building Lauda Air. The crash of one of his 767s in Thailand in May 1991, caused by a Boeing technical failure and claiming the lives of 223 passengers and crew, hit him hard.

In 2000 Lauda Air became a subsidiary of Austrian Airlines, and was later absorbed by it. Lauda meanwhile started a second airline under the Niki name, this time focussing on the budget market. More recently he would run a third airline, Laudamotion.

However, he never strayed far from motor racing, enjoying a long second career as a vocal and popular TV pundit who was never afraid to speak his mind. He managed to successfully dovetail that with management stints at three different teams. Spells at Ferrari and Jaguar bore little fruit, and his brutally honest assessments of any situation were not always well received.

Niki Lauda, Mercedes AMG F1 Non-Executive Chairman Photo by: Sutton Images

Then in September 2012 he was announced as non-executive director of Mercedes Grand Prix. Nico Rosberg had won the Chinese GP earlier that year, but at the time the former Brawn team was at best the fourth in the pecking order, and Michael Schumacher's comeback had been not been as successful as everyone had hoped.

However, Lauda knew that Mercedes was well advanced with its hybrid programme for 2014, and he played a key role in convincing Lewis Hamilton to leave McLaren.

In 2013, the last year with the V8 rules, Hamilton scored his first Mercedes win in Hungary, and Rosberg added two more successes. Momentum was building, and when the hybrids arrived in 2014, Mercedes was ahead of the game, and by some margin.

Lauda subsequently played a huge part in steering the team – working in conjunction with countryman Toto Wolff – to five consecutive double world championships, serving as a crucial link to the company's top management.

Over the years he had two kidney transplants, and last August he had a lung transplant. He had struggled with health issues ever since, and although unable to fulfil his usual hands-on role at the track, he remained in touch with what was going on at the track.

There's still a long way to go this season, but if Mercedes is ultimately able to secure a sixth straight double world championship in 2019, what would be a record-breaking achievement will stand as the perfect tribute to the man who did so much for the team, and for the sport as a whole.