Once a "mystery" benefactor was mentioned in association with a £50 million donation to the national stadium, JP McManus' name was not long in entering the frame. Wishing to maintain a low profile, McManus maintained a rigid "no comment" line when asked to confirm or deny he was indeed prepared to give that money. Far from diluting speculation, it only seemed to add fuel to the media fire. But that is nothing new for the 48-year-old businessman who now lives as a tax exile in Geneva and operates as a currency dealer. Myth and McManus seem to go hand-in-hand.

The original legend surrounded a fresh-faced ex-bookmaker who sent shudders down the spine of the Cheltenham betting ring in the early 1970s with gigantic bets. With time, the size of those bets grew even further in the public imagination. McManus was even saddled with the nickname of the "Sundance Kid" which suggested a swaggering figure cutting a swathe through the racecourses and the gambling rooms of Europe. McManus may, indeed, cut a swathe, but he has rarely swaggered.

Born in Dublin on March 10th, 1951, McManus grew up in Limerick far from the high-flying image that now accompanies him. Instead of the private jet he now owns, he was forced on more than one occasion into driving a bulldozer for Limerick County Council in an effort to finance his fledging bookmaking business.

Bookmaking, he quickly decided, was not for him. Bookmakers have to bet on every race. Gamblers don't. So McManus selected, gambled and usually won. The legend began to gather pace.

The stories of £100,000 bets are legend, but McManus has said: "A lot of it was nonsense and picked up its own steam. I've said this before, but the best strokes have never been told because they might have to be used again."

McManus now operates at a level where betting is a fun aside. As a tax exile he is allowed 280 days in Ireland over a two year period with not more than 180 days in any one year. In Ireland he lives at Martinstown Stud near Kilmallock in Co. Limerick.

In interviews, McManus dismisses talk of the good life in Geneva and the public fascination with his wealth, which has been speculated as being close to £400 million, as boring. The private jet he describes as "just a way of travelling". Racing has been a lifelong passion but he maintains strong links with the GAA and in particular the South Liberties club in Limerick. Former Limerick hurlers Pat Hartigan, Eamonn Grimes and Joe McKenna have had racehorses named after them. Golf is also an interest along with his friends Dermot Desmond and the Coolmore Stud boss John Magnier.

Golf has been the medium for previous charitable donations by McManus. In 1995, a golf classic organised by McManus raised £2.94 million which was allocated to various charities in the Limerick area. That figure included £500,000 which was paid at an auction for a cartoon by the artist Peter Curling entitled "A lot of balls".

McManus plans a similar two-day pro-am this summer with some of the world's leading professionals playing for a £400,000 prizefund at Limerick GC.

When asked about McManus, friends always allude to how "ordinary" he has remained despite his great wealth. He himself has said: "When I go out on a Saturday night it's with the same people I went out with over 20 years ago."

In horse racing, he is invariably known as just JP and his string of National Hunt horses are spread among such top trainers as Christy Roche, Arthur Moore and Edward O'Grady. Much the best horse he has owned, however, is the Aidan O'Brien-trained Istabraq, who has won the Champion Hurdle at Cheltenham for the last two years and is a long odds on favourite to make it three next March. Istabraq was a high-profile winner at Leopards town last weekend and afterwards McManus said: "It's a joy to own a horse like him."

McManus's £50 million contribution is conditional on the proposed new stadium carrying no sponsor's name, it must be accessible to all field sports and it must be state-of-the-art. Now that the Taoiseach has publicly thanked him for his £50 million contribution, McManus is steeling himself for a new crop of headlines. Contacted by The Irish Times last night, he declined to comment on why he has made his gift of £50 million. The episode looks like providing another chapter to the myth.