When Oversway won hurdle race at Limerick Junction (now Tipperary) on May 20, 1943, no one could have guessed that a training juggernaut was about to be unleashed on British racing and its brightest star was about to be launched - a star that shone brightly over an amazing 51 year career.

Oversway was the first winner trained by the legendary Vincent O'Brien who died at his home in Straffan, County Kildare at the age of 92. O'Brien was undoubtedly a legend and the yardstick for all trainers in the UK - and he will be for a long time to come.

O'Brien's remarkable success is mind-boggling. The man began as a national hunt trainer (jumping trainer) and had very little ambition towards flat racing. He set about carving a niche for himself in jumps racing and within a decade he had begun to cut a swathe through the sport.

He won his first Grand National at Aintree in 1953 with Early Mist, and then became the only trainer to win three consecutive Nationals, following in successive years with Royal Tan and Quare Times.

He also won four Cheltenham Gold Cups - winning three in succession with Cottage Rake - again the only horse and trainer combination to achieve that feat. He took the Cheltenham jumping festival apart - also winning three consecutive Champion Hurdles with Hatton's Grace - yet another record for both horse and the great trainer.

In 1951 O'Brien bought a 251 acre property at Rosegreen in County Tipperary to turn it into a state of the art training complex, deciding he would branch out into training flat horses.

That property has also etched its name into the psyche of every racing person on the planet - he named it Ballydoyle.

Many doubted O'Brien would make the transition to flat racing - but they were wrong as the master horseman set about taking out 6 English Derbies. His first Derby winner Larkspur, was ridden by champion Australian jockey, the late Neville Sellwood, followed by Sir Ivor, Nijinsky, Sir Ivor and The Minstrel - all ridden by Lester Piggott, and Golden Fleece, with Pat Eddery aboard.

Nijinsky was the last horse to win the British Triple Crown (2000 Guineas, Derby and St Leger) a feat he achieved in 1970. In all O'Brien won 16 British classics, apart from the six derbies, adding 3 St Legers, four 2000 Guineas, one 1000 Guineas and 2 Oaks to his tally.

He also won the King GeorgeV Stakes at Royal Ascot three times.

He won the first million dollar race run in the world when Piggott landed Sir Ivor the winner of Laurel International in Washington.

He also trained the winner of a Breeders Cup mile, Royal Academy. He won 27 Irish Classics, again incorporating six derbies and an astonishing 9 Irish St Legers. The French too felt his impact and he took three Arc De Triomphe's back across the Irish Sea, two courtesy of wonderful racehorse Alleged and one with Ballymoss.

O'Brien did it all in his career and his last winner as a trainer was Mysterious Way at The Curragh in 1994. It was O'Brien who bought John Magnier into racing and upon his retirement they bought Ballydoyle for Coolmore and installed Aiden O'Brien as their trainer.

O'Brien won several training premierships in the UK and Ireland and still holds the record for 16 training premierships in the Emerald Isle.

Since his retirement O'Brien spent a lot of time in Australia, as his son David lives in Perth and he only recently returned to Ireland when he became ill.

David is one of five children Vincent O'Brien and his wife Jacquline had in a marriage that spanned longer than his training career.

The flags will fly at half mast at Epsom Downs right throughout the English Derby carnival and on Saturday all jockeys riding in the race will wear black armbands as a mark of respect and remembering the achievement of O'Brien.

For the true racing afficionado, for anyone who has ever remotely followed British racing, has ever walked along the ground floor of the grandstand at Royal Ascot and read the honour rolls for the major races, walked through "The Derby Walk Of Fame" at Epsom, they will leave with the name Vincent O'Brien firmly emblazoned in their memory.

What a career and what a life!