You turn professional when you are 16 and have finished with school because, as likely as not, playing golf is all you have dreamt about for years. Or you do so when you are in your early twenties after winning a scholarship to the United States and playing college golf there for three years. What you do not do is turn pro at 48, when your physical powers are on the wane and you are surrounded by powerful young men half your age.

On the other hand, if your name is Gary Wolstenholme and you are perhaps the most-capped amateur golfer in the world and a bachelor in love with golf, out of work, unable to sell your home and living with your mother to save money, you turn professional on a grey day in September shortly after your 48th birthday.

Wolstenholme conventional, normal? Never. How could he be? He travels with his own pillow and listens attentively to his biorhythms. “Gary's got every foible known to man,” Peter McEvoy, the captain of the 1999 and 2001 Great Britain and Ireland Walker Cup teams and a former amateur partner of Wolstenholme's, said. “He's a complete one-off.”

This morning Wolstenholme will describe himself as a professional when he submits the entry form for the first stage of the pre-qualifying process that he hopes will end in him playing regularly as a professional. The four-day qualifier is to be held at Dundonald, near Glasgow, next week. But already the benefits are accruing for the newest pro in the game as word of his change of status leaks out. Yesterday morning he was invited to compete in this month's Kazakhstan Open, an event on the Challenge Tour that is being held at the same time as the Ryder Cup.

“I have been thinking about turning pro when I get to 50 for some time,” Wolstenholme said yesterday. “And then I thought to myself, ‘There is not much more to do.' I have won 218 caps for England, won the Amateur Championship twice, as well as more than 70 tournaments on all five continents. I was 48 last month and I suddenly thought, ‘I am not preparing myself properly for when I am 50. My golf is not improving. Why don't I turn pro now?' And so I did.”

In a career as a top amateur that started in 1988, when he represented England for the first time, Wolstenholme places England winning the World Amateur Team Championship in Chile in 1998 as the best moment. “For us to beat the best amateur golfers in the world was huge,” he said. “Bigger even than my beating Tiger Woods [in the Walker Cup in 1995]. We won the World Championship, in effect, and I stood there with a gold medal around my neck watching the flag being run up the pole. That was really special for me.”

Wolstenholme is known not only for his foibles and his talkativeness but also for being one of the shortest hitters to reach the top of the amateur game. To compensate, he developed exceptional accuracy and a devastating short game to go with good mid-iron play. In addition - and this is not an insignificant attribute - he has always risen to the occasion. He loved the limelight, even when he was being outdriven, and at matchplay he revelled in the irritation he caused to young opponents, who would berate themselves for being outplayed by an old man who was so short off the tee.

A glimpse of Wolstenholme's new world came in the US Open at Torrey Pines, near San Diego, in California, in June. His rounds of 83 and 82 left him far from reaching the last two rounds and nearly £1,000 less well off after paying his expenses. But you never catch Wolstenholme talking negatively. There is good in everything he does and on this occasion it was the way he had won through the qualifying rounds at Walton Heath when playing alongside Daniel Vancsik, the Argentinian, who is 31 and hit the ball much farther.

“He was 80 or 90 yards past me off the tee, but at the end of two rounds we were on the same score,” Wolstenholme said. “That pleased me. I am not going to win 20 events in the few years before I turn 50, but I hope my golf will improve, I hope I can stay fit and I hope I can show some form.”

Amateur dramatics

- Born Aug 21, 1960, Egham, Surrey

- Represented England 218 times

- Played in the Walker Cup six times (1995, 1997, 1999, 2001, 2003 and 2005), beating Tiger Woods in the singles in 1995 at Royal Porthcawl and Anthony Kim in the singles in 2005 at Chicago golf club

- Became Great Britain and Ireland's biggest points earner in the Walker Cup, with ten from 19 matches, when he won his singles in 2005

- Amateur champion at Ganton in 1991 and at Royal Troon in 2003 when, at 42, he was the oldest player in the field