Constitution Hill a once-in-a-lifetime talent but racing offers no guarantees

The trainer Nicky Henderson with Constitution Hill at his Seven Barrows stables. The six-year-old is as short as 1-3 for Tuesday’s Champion Hurdle. Photograph: Richard Heathcote/Getty Images

One of the earliest recorded uses of the phrase “a racing certainty” appears in the Monthly Magazine in October 1837, in an article recalling the St Leger of 1834. Plenipotentiary – or Plenipo to his fans – was the odds-on favourite, having won an unusually strong running of the Derby at Epsom earlier in the year.

“Plenipo, after beating the best lot of horses probably ever seen in the south of England, was sent to Doncaster,” it recounts. “If ever there was a racing certainty, it was that, barring accidents, he must win the Leger.”