For the rest of his career – and maybe the rest of his life – Marc Warren will never be able to forget Sunday, July 15, 2012.

It was the day he was ordained to be a sporting king of Scotland, earn himself an extremely fat cheque (almost half a million quid) and be lauded by his countrymen and the media. But he stood on a banana skin and took a skite.

As I discover during hours of conversation with Warren recently, the so-called glamour of being a professional golfer is not all it's cracked up to be – not when you are frantically chasing bargain-bucket flights from one country to another to play events, sometimes with your dirty laundry piling up. But it does have its moments offering fabulous wealth, such as the one that should have been Warren's last summer.

As the year closes the Rutherglen golfer still suffers minor twitches at the thought of what happened to him at the Scottish Open, one of European golf's richest events. With just four holes of the 72 remaining, Warren held a three-shot lead, and blew it. That night, being driven down the A9 by his wife Laura to their home in Glasgow, he turned to her and said, "Excuse me, I need to do something," before shoving his head out of the passenger window and yelling: "F***!"

"I felt a bit better after that," says Warren. "It would have been the greatest win of my career, in front of home fans. But it wasn't to be. For the rest of my life it will be the one that got away."

Those of us who were there that day at Castle Stuart, Inverness, will never forget it. I was commentating for Radio Scotland and had the good fortune (so I thought) to be sent out to follow Warren's match for the final round. By the time he went birdie, birdie, birdie from the 10th through the 12th to open up a three-shot lead, the vast crowds were hollering and we appeared to have a major Scottish sporting triumph on our hands. "I am standing here watching the champion-elect and it is a thrilling scene," I intoned down my microphone with an absurd and premature solemnity.

One hour later Warren would be standing on the 15th tee, the victim of a delay up ahead. His round would abruptly go off the rails. Over the next three holes he dropped four shots, sacrificing a comfortable lead, suddenly requiring a birdie on the last just to make a play-off with Jeev Milkha Singh and Francesco Molinari. The "champion-elect" didn't make it, and finished tied for third.

"If I had won it would have opened up a lot of doors for me," says Warren. "I'd have got automatic invites to a lot of big tournaments; in fact I'd have been pretty much guaranteed any event I wanted to play in. My sponsorships would have gone up, I'd have got into the Open Championship this year and next year. It would have been huge for me, I don't deny it. When I came off the course that evening I thought to myself, 'You know what, I should be collecting the trophy and making a speech right now.'"

I need to ask Warren a very touchy question. All across sport the "mental collapse" has been witnessed in all its infamy: a sports man or woman is on the verge of greatness, having just about beaten the field, but wilts amid the heat of reaching out for the prize. There have been many ignominious cases of it. It involves the part of the brain which says, "I can do it, I've beaten them all off," but lacks the confidence to go and ultimately grab the trophy.

Did Warren wilt under the pressure? It seems a fair enough question, to which he offers a convincing answer. "No, I don't think I did. I've won four times as a golfer before and they have all been won via a play-off. So I've handled the heat before. In fact, I've felt way more nervous on a golf course than I did at Castle Stuart. When I won in Sweden in 2006 I beat Robert Karlsson in front of his home crowds. So I've been in much tougher situations.

"I just made some decision errors. If I could change anything I'd have played a 2-iron instead of a 3-wood off the 15th tee, which is where my round started to go wrong. But I felt confident. I was standing on the tee, and there was a bit of a delay, and I ended up hitting my 3-wood into rough. All weekend I had been hitting any shot I wanted – a left to right, a right to left – so I tried to hit a fade. I had actually felt overconfident."

What happened next is still painful to recall. Warren dropped four shots over three holes – 15, 16 and 17 – which included one unplayable lie and a missed putt from three feet. There was sudden disintegration. Out on the course spectators looking on from afar were asking: "What the hell has happened to Marc Warren?"

"I lost concentration after that," he says. "By the time I got to the 18th tee I just felt I couldn't get myself up for it. I felt deflated. There was another delay and I ended up looking out over the Moray Firth, and I couldn't get myself switched back on.

"Three times previously I'd needed a birdie on 18 to get into a play-off, and three times I'd done it. But when it finally came to playing that last drive at Castle Stuart, I took the driver out my bag and said to my caddie: 'Right - Birdie for a play-off here, right?' He said to me, 'Aye, birdie for a play-off.' But I wasn't up for it, and I could tell looking at him that he wasn't up for it either."

There was an added poignancy about Warren missing out at Castle Stuart, because every week he says he feels the need to prove himself. The truth is that when Warren turned professional in 2002 he was one of the hottest young golfers in the world. Despite having won two European Tour tournaments so far, he has probably not lived up to some of the early billboards.

"I was about the best amateur in Europe at that time," he says. "I'd holed the winning putt in a Walker Cup, and when I turned pro I was playing off plus-5. I think I was the lowest-handicapped, highest-ranked amateur in Europe.

"I had offers from all the top brands – Nike, Titleist, Ralph Lauren. Looking back, I guess some people were expecting big things."

Just two weeks ago his nearly-man status struck again. After two rounds of the monied World Tour Championship in Dubai, Warren shared the halfway lead with Rory McIlroy and Luke Donald, two superstars of golf. But he then shot 72 and 73 to finish in 26th place. "I know I have the talent – plenty people tell me," he says, a touch ruefully.

Let's cut from the near-glory to the drudgery of professional golf. Nobody is deluding themselves that it is a bad life – who wouldn't want to be a professional sportsman? – but Warren makes it plain that, with nearly 50 tournaments to go chasing every year, the glamour and the constant globe-trotting quickly wear off.

For the top golfers – the Rory McIlroys, the Tiger Woods – life is a gilded paradise. But for the rest the prizes are there to be claimed, but not without the hassles.

"If you are doing this week after week it can get pretty wearing," he says. "The Scottish Open, for example, was the last of six tournaments in a row, and that included going to America. Sometimes it's not easy keeping on top of your laundry.

"Usually you fly out on a Tuesday morning to a tournament – or if it means two flights for me from Glasgow, then I leave on a Monday – so you can play a practice round on Tuesday afternoon. Take Crans-sur-Sierre in Switzerland – that's one of the toughest venues to get to. I fly Edinburgh to Geneva on easyJet, then take a two-hour train ride to the bottom of the mountain, then grab a lift for the half-hour drive up to the club.

"Coming the other way, if you miss the cut on a Friday then you're charging off the course to get to an airport as soon as possible. Or you can be at a tournament where, depending on where you finish – or when you finish – you can miss your flight getting out on a Sunday night, so you have to stay over until the Monday. You can end up floundering around."

But, I ask Warren, surely this isn't the way of it for the top guys – the Rorys, the Tigers? These players virtually have man-servants who do everything for them. Certainly, with his new-found fame and wealth, I can't imagine McIlroy sprinting off to an airport, his clubs over his shoulders, frantically trying to grab a cheap flight.

"It's very different for the top golfers," says Warren. "They get better treatment – free hotels, free this, free that. It's fair enough. Without these guys the tours wouldn't have the sponsors. They even need to be seen on TV at certain times for visibility – these guys are never the first ones out at 7am or last out in the day.

"The better you get at golf, and the richer you get, the fewer expenses you have. For example, Ryder Cup players get free hotel rooms for two years in every event they play – guaranteed. Sponsors will happily pay for these guys' hotel rooms to get them playing."

And there is a minor sting in this caste system. "In reality it's the ordinary guys who end up paying for the big names' hotel rooms. If you are the defending champion, you'll get a free hotel room most weeks. I've had a free room at Gleneagles ever since I won there in 2007. I won a tournament in Sweden – I've had a free room there ever since. But what a hotel will do is, if it is normally £100 a night, it will give out 10 free rooms to the top players, but charge the rest of us £150 a night. So we end up paying for their rooms!

"I remember in Sweden once an unsung tour player arrived late for a tournament and he sussed out where the players' hotel was. We were all in there and paying £120 per head a night. But this guy went on to some site and got a room in the same hotel for 40 quid.

"As players I think we subsidise quite a few hotels. We routinely stay in places which are £80 a night before a tournament, and £80 a night after a tournament, but for the week we are there it is suddenly £150 a night."

Laura travels with him a lot of the time, which Warren says takes away some of the tedium of the recurring checking in and out of hotels and the long, drifting hours when not out on the course. "Laura hates golf, so it is perfect," Warren says.

"It's great having my wife out on tour with me. Otherwise, quite a lot of the time you'd be left hanging around if you're not on the course. In Asia, for example, there are quite a lot of tournaments where there is nothing to do – you are just a golfer, left hanging about in a hotel with 300 other guys. I can't speak for other golfers but I'm glad to have my wife with me."

On the night of the Castle Stuart disappointment it was Laura who got Warren back on an even keel. Seeing how well her husband had been playing, she had already bought some champagne to be consumed in celebration. When it didn't quite work out, Laura took a grip. "She decided we were still going to drink the stuff," he says. "So we drove home that Sunday night and picked up a Ho Wong as usual. I just thought, 'Right, I still need to treat myself.' We sat and talked about it and realised that it had still been a great week.

"My wife then opened the champagne and we drank it. I realised anyone who has ever been successful at anything has also missed out on things: in golf, in football, whatever.

"There is no real disappointment for me any more. I wish I'd won it, and I'd loved to have been the Scottish Open champion. But it doesn't hinder me. I don't dwell on it. In fact, I've shown I've taken a lot of confidence from finishing so high on the leaderboard – I've been playing pretty well since."

Just for clarity, I double-checked the career earnings of this supposedly unlucky 31-year-old golfer. Since 2002, Warren has earned around £3 million. In a certain vulgar fashion, I waded through these figures with him, and Warren's gratitude for what he has is pretty sincere.

"I feel very fortunate to have such a long career," he says. "If I was a footballer my career would be ending soon. But in golf, from here to 40 is when you play your best.

"But you've still got to do it out there. In golf, you don't get paid if you don't play well. You feel as if you've got to prove yourself every week. I finished third at the Scottish Open but missed the cut in my next tournament. So you always feel you have to deliver. Every week is an opportunity to win.

"You can never go backwards in golf. In terms of career earnings there are no guarantees. You've got to earn. I looked at the career earnings of Rory McIlroy earlier this year on the European Tour alone and it was something like £11.2 million. I thought: 'Wow!'

"Listen, I am so lucky in what I do. But I've learned this year, of all years, that nothing is guaranteed." n