The M23 had plenty of development left in it for 1974, and the really significant change was the creation of the Texaco-Marlboro McLaren superteam, as 1972 World Champion Emerson Fittipaldi quit Lotus to join Denny in M23s that were now painted red and white. It was a major coup for McLaren that brought in the sponsorship dollars to stage a major title assault, but a high degree of juggling was needed to placate Yardley. In the end, agreement was reached to run a third works car in its livery. Teddy Mayer's initial plan was to run Peter Revson in it, but the American finally lost patience with the ongoing negotiations and left to join Shadow in a decision that would ultimately cost him his life when he was the victim of suspension failure during testing at Kyalami, in his place, Phil Kerr would run the M23 for Mike Hailwood.

Prolonged winter testing by the enthusiastic Fittipaldi at Paul Ricard led to changes to the car, such as a longer wheelbase and wider track, based on his considerable experience of the Lotus 72. Years later, historic racer Willie Green would call it “easily the best” of the many 1970s Formula 1 machines he had driven round Brands Hatch. Good aerodynamics, he contended, "were one of its strong suits and the lack of buffeting in the cockpit at high speeds bears this out.”

Gordon Coppuck described the car as a decade and a half on as, “The best F1 car for three years. Yes, it was a good design, but it also benefited from a lot of good development. The chassis changed very little, but we did a great deal of suspension work to keep it competitive. The chassis was much stiffer than those of our rivals’ cars, but it was pretty flexible by modern standards.”

Compared to the previous season the M23’s weight distribution had been improved by fitting a new bellhousing spacer between the engine and gearbox, hence the three-inch longer wheelbase. With an additional two inches of track, traction was also improved out of slow corners, while the rear wing was brought forward by 10 inches in order to comply with a new set of regulations. During the season three different wheelbase variations were employed, together with a distinctive narrow 'winklepicker' nose which saw service at Brands Hatch, Jarama and Monaco where its wider wings generated more front-end downforce.

Fittipaldi loved testing. According to Coppuck, “He enjoyed this side of his job more than the races.” That was to prove a valuable factor as a tough season progressed. It began superbly for the new team, though it was Denny who won the opening race in Argentina after passing Reutemann’s ailing Brabham with two laps to run. Emerson inadvertently delayed himself while in a position to challenge for the win by knocking off the ignition. He finished 10th. But the Brazilian did not have to wait long to make amends, as he won his home event from pole position, finishing 13s ahead of Regazzoni.

ln a year characterised by the battle with a newly emergent Ferrari team and its drivers, Niki Lauda and Clay Regazzon and the threats from Reutemann, Tyrrell’s Jody Scheckter and Lotus’s Ronnie Peterson, all of whom enjoyed victories. Emerson won again in Belgium and Canada to head into the final race, at Watkins Glen, neck-and-neck with Regazzoni.

In the Yardley car, meanwhile, Hailwood had some strong races, most notably the Dutch GP where he matched Fittipaldi as he raced home fourth behind the Marlboro car to add to another fourth in Argentina and third in South Africa. But his F1 career ended when his M23 landed badly on a jump at the Nurburgring and crashed heavily inflicting leg injuries. David Hobbs drove the car in Austria and Italy before upcoming German Jochen Mass left Surtees to take over the car for the two final races.

The American shootout went Emerson’s way as he brought the M23 home fourth to clinch his second worId title, and the first-ever World Championship for the McLaren marquee. That day was historic for two other reasons: it marked the end of McLaren’s association with Yardley; and Denny's final Grand Prix appearance. His engine failed after four laps. Without The Bear’s mountainous courage in the aftermath of Bruce's death, there might not have been a McLaren team for Fittipaldi to drive for.

The M23's outstanding combination of performance, predictable and controllable handling, superb preparation and reliability had left an indelible mark in the record books.