James Hunt's McLaren M23 crossed the line first at Jarama, comfortably ahead of Niki Lauda's Ferrari, in a result that looked straightforward enough on the day. It was anything but. Post-race scrutineering found that Hunt's car was marginally too wide — measured at 1 millimetre over the maximum permitted width across the rear tyres, a discrepancy invisible to the eye and with no plausible performance benefit, but a breach of the regulations all the same. Hunt was disqualified, and the win, and the points that went with it, were awarded to Lauda.
McLaren appealed immediately, arguing the discrepancy was marginal, unintentional, and irrelevant to the car's performance — the tyres had simply spread slightly under racing loads and heat. The appeal process dragged on for months, through the heart of the 1976 season, with Hunt racing on not knowing whether the Jarama result would ultimately count in his favour or against it. In September, well over four months after the race itself, the appeal succeeded: Hunt's victory and full points were reinstated, and Lauda's win downgraded back to second.
The restored points mattered enormously by the time the season reached its dramatic conclusion at Fuji in October, where Hunt clinched the World Championship by a single point over Lauda — a margin so narrow that the four months of bureaucratic wrangling over a millimetre of tyre width at Jarama had, in a very real sense, decided the destination of the 1976 title.