Scottish showjumper Scott Brash on the road to Rio

Brash is the world No.1 showjumper, only rider to complete a unique treble of grand prix victories, in Geneva, Aachen, and Calgary. This carried a bonus of almost £750,000, biggest in his sport.

Despite this, the Borderer did not make the BBC Sport Personality short list. "I'm more disappointed for my sport than personally," he says philosophically. "It had never been done, so you feel that if we don't get recognition for that, it's a bit disappointing. You can only try to make the sport's profile higher."

He and his sister, Lea, were given a pony to share when he was seven. "I was a cheeky little bu**er and took quite a few tumbles to start with, but Minstrel was a great start-off pony. I got the bug for jumping and dad got us registered with British Showjumping when I was about 10."

But how does a Border builder's lad graduate to a £2m gelding? "Just very, very, lucky," he says, self-effacingly ignoring the sporting axiom that one makes one's own luck. "The call came out of the blue. I'd won the World Cup in Toronto on a horse we'd bought when he was young, and brought him up through the levels.

"When I arrived home, I got a phone call from Lord and Lady Harris, and Lord and Lady Kirkham. With the Olympics coming up, they wanted to buy a horse that could potentially go, and said they'd like me to ride it.

"I am just so lucky to have met them. We have such a great relationship. We speak almost every day on the phone. They're like my family. I'm like their son, sort of thing. It's a very close, wonderful relationship. I am so glad to have met them, not just for my sport, but outside. They are fantastic role models."

Lord Harris of Peckham is chairman of Carpetright, while Lord Kirkham is founder of the DFS furniture empire. They bankrolled the purchase of the Dutch-bred horse from a Ukrainian gas millionaire. Brash rushed from a show at Bishopton to Germany with veteran showjumper and Olympic bronze medallist David Broome, to inspect the horse. After just 45 minutes, Scott pronounced him a winner. Just before expiry of showjumping's equivalent of the transfer deadline.

The pair finished fifth in 2012 as Britain won team gold. "I'd hoped for more individually in London. I set high goals, but realistically, I'd have been one of the underdogs. In my own head I was driven and wanting to win, so I was very disappointed.

"I'd only been riding the horse for six months - a very short time at this level. I was one fence, one knock-down, from jumping off for another gold or silver medal. When you are so close, potentially, to doing the double, it's disappointing, but looking back, it was a fantastic achievement to come fifth."

When asked by Clare Balding what the medal might mean to him, he ventured: "Hopefully it’ll help me pull more women."

The quip inevitably haunts him. So what might another gold do? He is cautious, looking forward to Rio. "If it was next week, for sure we'd be on the team. He's in good shape, but horses get injured just like any athlete, and can get injured easily."

Unlike athletics or swimming, showjumping is more of a lottery. "If you ran the Olympic showjumping 10 times, I think you'd get 10 different winners. In other sports I think you'd get pretty much the same result. In five-star grand prix showjumping it's nearly a different winner every weekend.

"There so much can go wrong, and so much has to go right. And it's not just us that has to do everything right. The horse has to as well."

He dismisses the Formula 1 analogy, the suggestion that it is not the driver, but the car. "Anyone who knows or is involved in the sport knows it is a partnership, maybe 60/40, with 60% being the horse, 40% the rider. Success comes with a really strong partnership. You could have the best rider in he world and the best horse, but if they don't get on, they won't be successful. You could be the best rider, but if you don't have the best horse, you won't get anywhere."

Sanctos has just turned 14, and Brash reckons Rio will be his last big championship before retiring: "hopefully at the very top. My owners have turned down lots of different offers. Lord and Lady Harris have owned horses for over 50 years, and one of their biggest goals in life was to win an Olympic gold medal.

"To do that in their home country was a dream come true, as it was for me. Sanctos has done so much for them that they'd never want to see him go to another home. They've said he will spend the rest of his life with them."

Brash moved from Peebles to West Sussex last year, bought a yard and built a new outdoor school. "It was getting too difficult, travelling from Scotland to Europe where most shows are - too tiring for horses and staff."

This weekend he is at a World Cup event in Bordeaux, then Spain for two weeks, before competing in Doha.

Fellow Borderer Ian Stark won four Olympic silver medals, and World and European eventing gold. Brash met the Selkirk man for the first time last year. "What a wonderful, down-to-earth, humble man. It's nice to know someone in the equestrian world, competing at such a high level, comes from the Borders. It's good to know that your dreams are possible, that nothing is impossible."

Brash would like to see betting introduced to show-jumping. "It's an interesting sport and hard to pick a winner. There's the odd show with a betting booth, but in Spain they have Tote betting, and it's very successful."

He sees no end to his competitive career, citing 69-year old Canadian Ian Millar, Beijing 2008 silver medallist, who has just qualified for a record eleventh Olympics. "We are fortunate that we can ride for so long.

"I can't see me doing anything other than something to do with the horses. It's all I know."