Frankel would provide a more definitive test than the Triple Crown

Son also rises: Joseph O'Brien, son of trainer Aidan, with the Derby trophy (PA)

Typical. You wait all these years for a Triple Crown horse, and two come along at once. True, as London bus syndrome goes, this was closer to the coach that careered through the film, Speed, than the open-top double-deckers that gazed upon Camelot as he duly separated himself from his inferiors in the straight here yesterday. In this instance, admittedly, all that would have exploded – had he slowed down – was a reputation. As it was, the Derby was won with such an overwhelming show of horsepower that everyone is already talking about the first Triple Crown since Nijinsky in 1970.

Admittedly, only two horses have been eligible to try in the meantime and both declined the St Leger. In contrast, the Americans have been tormented by several near-misses since Affirmed last achieved the equivalent distinction, in 1978. This Saturday, however, their craving may at last be satisfied when I'll Have Another lines up as favourite to add the Belmont Stakes to his wins in the Kentucky Derby and Preakness.

The American Triple Crown is a different challenge. Its three legs require less versatility – the race distances are divided by two and a half furlongs, rather than six – but a time-frame of just five weeks makes it no less demanding. The biggest difference, however, is its status as a genuine and defining obsession to fans and professionals alike.

Here the Triple Crown has flirted with obsolescence. And, before everyone hastens Camelot headlong to Doncaster in September, it is worth remembering why that should be so. Yes, commercial breeders have distorted the relative importance of speed and stamina in the thoroughbred, so that success over the longer distance of the St Leger is seen as inimical to the reputation of a young stallion. In principle, you would presume it a guarantee of precious bequests to future generations, hardiness and constitution and staying power.

In reality, Sea The Stars considerably increased his stud appeal – and fee – by winning the Arc instead. But if that seems reprehensible, then it would be wrong to pretend that the Leger could only ever be abjured on some avaricious whim.

Nijinsky was beaten in both subsequent starts after the Leger. Vincent O'Brien, his trainer, felt that the champion had "lost his fire". And if the scene here yesterday seemed seamless – the same nostalgic charabancs in the background, in the same mute witness – then the destiny of this new paragon should not necessarily be viewed as inexorable.

He is housed at the same Co Tipperary stable as Nijinsky and trained by another O'Brien – a man achieving things beyond the reach even of his great namesake and predecessor. His patrons at Coolmore Stud are themselves so good at what they do that they can more or less prescribe a new fashion at the yearling sales. If John Magnier and partners decide that the Leger should be restored to vogue then that is what will happen.

It would seem impertinent, then, to advise them of their own best interests. But that applies equally to any who now propose the Leger as an inviolable imperative for Camelot. He has still only had four races. If the fifth is going to undermine his longevity then there is a case for wondering whether it should sooner be against Frankel than against the margins of his own physical capacity.

Frankel, the unbeaten champion of the previous crop, hailed as invincible, is likely to venture beyond a mile this summer. If Camelot were to meet him halfway, then some of us would be perfectly prepared to see another year of dust settle upon the Triple Crown.