Michael Phelps is the most decorated Olympian of all time. But is that the same as being the ‘greatest’? That was the question left hanging in the air after the swimming superstar won the 19th Olympic medal of his career by anchoring the US 4x200m freestyle relay team to gold in London on Tuesday. That saw him overhaul the record of 18 medals amassed by Soviet gymnast Larisa Latynina between 1956 and 1964. Phelps’s haul, which includes 15 golds, is outstanding. But swimmming opens itself up to producing multiple-medal winners by having categories for styles as well as distances. So while athletics has the 100m, in swimming the distance can be covered in several different ways. And there are those who argue longevity is a key factor in determining greatness — Phelps is still only 27 and his medals have been amassed over the space of just three Games. However, longevity wasn’t an option for Jesse Owens, who overcame barriers of racial prejudice to win four track and field golds in Berlin in 1936 and was then stripped of his amateur status for accepted a few commercial offers. And even if he had still to be allowed to compete Owens, like many contemporaries, would have seen his career cut short by the Second World War when the Games were suspended. That Phelps could even contemplate winning eight gold medals at a single Games, as he did four years ago in Beijing, was in a sense only possible because fellow US pool great Mark Spitz had, 36 earlier, won a then record seven — and all in world record times — at Munich.