When the vastly more experienced Graham Hill was in negotiation to join him at Mecom Racing as a late replacement for the 1966 Indianapolis 500, he simply asked that he be given the same as Jackie Stewart was getting: a request that was as shrewd as it was fair, for the younger gun was already noted for striking a hard bargain. Hill would win that race – but only after the sister Lola of his BRM F1 team-mate and fellow rookie had coasted to halt 10 laps from victory. Stewart would have to settle for sixth, the Rookie of the Year award – and $25,767. 

It was not yet possible for a professional racing driver to survive on F1 alone, though its increasing commercialism from the end of the decade and Stewart’s business example would soon make it so. In the meantime the man himself could not resist the draw of the lucrative Can-Am series and he agreed to handle a Lola – “the worst car I ever drove” – for Carl Haas in 1971. Between winning grands prix and ultimately the F1 title, he would jet back and forth across the Atlantic. This made him a lot of money – though not as much as he had hoped given McLaren’s continued supremacy – but also made him ill. Inexplicable spins while testing a McLaren in readiness for the 1972 series coalesced his suspicions: a doctor grounded him for six weeks.

Such diversification was then the norm and its benefits were not only financial. As Stewart’s F1 path meandered with a misdirected BRM from 1966-67, the more fruitful F2 battles with Clark in more equal equipment (especially in 1967) provided a much-needed boost to his confidence. They also allowed him to create, form and build a partnership with Matra: initially unconvinced, he was astounded by the French marque’s build quality that would give it an edge in F1.

Diversification also provided memorable footnotes as well as introducing him to new and sometimes left-field technologies that kept his mind alert to required new techniques: the lag and left-foot braking of the Rover-BRM Turbine at Le Mans in 1965 and the increased g loadings generated by the fan-assisted ground effect of the Chaparral 2J Can-Am car that he drove at Watkins Glen in 1970.

It provided him with the halcyon Down Under trips – an extended winter-sun holiday interspersed with serious racing – of the Tasman Series: he scored four wins with BRM to beat Clark to the 1966 title, but had to give best to him the next year when a string of retirements undermined two more wins.

It provided him with his only outing as a Ferrari works driver: second place as co-driver to an under-the-weather Chris Amon in a 330 P4 – “the most beautiful car I ever drove” – at Brands Hatch’s BOAC 500 clinching another World Sportscar Championship for Maranello.

And then there were the what-ifs. But for that broken wrist he would have driven a four-wheel-drive Lotus turbine ‘wedge’ at Indy in 1968: replacement Joe Leonard put his on pole and was nine laps from victory when it became silent as opposed to merely eerily quiet. And Stewart might have contested Le Mans for a second time if insurance concerns hadn’t scuppered  Steve McQueen’s dream of sharing a Porsche 917 with him in 1970.

Increasingly, however, the money generated and focus demanded by Stewart-era F1 militated against extracurricular racing. Stewart contested his last F2 race in 1970 (in a Brabham entered by John Coombs) and, following his health scare, only the financial/political clout of Ford persuaded him to venture beyond F1.

He co-drove a Capri in selected European Touring Car Championship rounds, in 1972 (finishing second alongside François Cevert at Paul Ricard) and 1973 (sharing with Emerson Fittipaldi at the Nürburgring but retiring because of a failed head gasket.) These were outings that persuaded him that all categories of the sport were becoming more specialised.

It was Hill who completed a unique triple crown – the F1 World Championship (two of them plus five Monaco GP wins), Indy and Le Mans – by winning the latter race in 1972 with Matra. Might Stewart have attempted it had he won at Indy? (In 1967 he had been pressuring eventual winner AJ Foyt for second place when his Mecom-run Lola’s Ford engine again lost its oil pressure.) Probably not. Besides, the point is doubly moot, for he was at the time convalescing at his Swiss home and, illness aside, rather enjoying it. Recovered, he quickly battled back to fitness and promptly won the French GP at roller-coaster Clermont-Ferrand upon his return.

His decision to retire was not to be rushed. He had already begun to mull it over after Jo Bonnier’s death at Le Mans. Stewart would never lose his fascination for motor racing or driving but there were other, safer ways to earn a buck.