SPORT facilities at Loughborough University are state of the art: “The best integrated sports development environment in the world” according to its most famous graduate, Sebastian Coe.

Yet since leaving it, and opting for a shoestring alternative on the banks of the River Tweed, Guy Learmonth has made the most dramatic men’s 800 metres break-through by any Scot in a generation. Having reached the World semi-final in London, on Tuesday he clocked 1min 45.10sec in Italy: from a modest 43rd on the UK all-time list, into the top 20; second in Britain this year and second behind Tom McKean in the Scottish all-time rankings.

He overtook three successive Scottish 800m record holders: Frank Clement, Paul Forbes, and Graham Williamson, 2015 national two-lap champion Jake Wightman, and multiple Scottish 400m champion Brian Whittle – good enough over 800m to finish fourth in the Commonwealth Games ahead of the world record-holder, the future Lord Coe.

“I’ve always believed in myself, but it’s been a rough two years since the Commonwealth Games,” said Learmonth.

Rough? His coach, Henry Gray, said: “He might have walked away, but after personal bests indoors and out, and making the European Indoor and World Championship teams, I think he can medal at next year’s World Indoor. McKean’s indoor record is in grave danger and even his outdoor one is within reach.

“Yet we’ve struggled big time, taken huge risks financially. I’ve put myself in a perilous position these last six months, because I knew Guy was good enough to get to the top.”

The GB two-lap top-20 seems set in stone. Guy is only the second addition in five years, and third in a decade - a second behind former Olympic champion Steve Ovett. Indeed, Guy ran faster this week than Ovett’s Moscow gold-medal time in 1980.

McKean won European titles indoors and out, and set the Scottish best (1:43.88) before Learmonth was born. In 1993, he won the World Indoor title in Toronto, and no Brit has won since.

Quarter of a century on, the event is in Birmingham next spring. “McKean’s record has been a big motivation,” says Guy. “I want to break his records, and the more I say that, the more I believe I can. I know I can break them, indoors and out.”

His season is staggering given what he turned his back on. Sixth in the Glasgow 2014 final at 22, the world seemed at his feet on his return to Loughborough, focal point of the UK Athletics coaching system, globally-acclaimed sport science, and a battery of medical facilities.

George Gandy - who coached both Coe and Williamson - steered him from 1:49 to 1:46, but it stopped happening. Guy switched to Rob Denmark, former Commonwealth 5000m champion, but managed only 1:47 last year, missing the Olympics. He was devastated.

Learmonth explains his return home: “I’ve the greatest respect for George and Rob, but it was not working for me. I should have kicked on after the Commonwealths, but there was a lot going on off track: terminal cancer, family bereavement, a friend in a coma and paralysed after a car crash. It was hard holding it together.

“My family support me, and I’m grateful to New Balance who’ve stuck by me. Scottishathletics help, but there’s no UK Lottery support for me or my coach, and I believe we both deserve it.

“There were some dark periods, mainly due to motivation, but if I’d quit, I’d have regretted it for the rest of my life - the what-ifs.”

Gray had taken Guy for swimming lessons aged four. “He’s been a family friend for ever. When I started running at 16, it was he who coached me. He knows me inside out in a way they could not do. That’s no disrespect.

“I’d everything at Loughborough and came home to no resources, no facilities, no track. It’s an hour to Tweedbank track, so we train on a path on the river bank, clear off ice in winter, do circuits on concrete with cars driving past. Henry keeps a wheel in his car boot, for measuring out for sessions.

“There’s a kilometre straight which he and dad marked out every 100 metres in Roman numerals. I do 1000-metre reps there.”

Learmonth senior, a sprinter who trained with former Olympic champion Allan Wells, stands at one end, counting down the start, into his phone. Gray listens at the other end, holding the stopwatch.

A dentist, his father converted the family garage into a gym. The equipment includes speed balls like those he and Wells once used. Guy now works on them.

Gray’s uncle, and his father (also Henry) coached many Scottish champions in the traditional Border pedestrian style. “I first went with my dad to the track at seven.”

Today Guy is running a 500m time trial by the Tweed, a warm-up for his last race of the season on Newcastle Quayside next Saturday. The field includes Commonwealth 800m champion Nigel Amos and Guy has been called out on Twitter by World relay bronze medallist Martyn Rooney. They have been winding up one another since they were photographed last week outside No 10 Downing Street.

An old coaching adage has it that every athlete is an experiment of one. The basic principles apply to all, but the fine-tuning is why coaching remains as much art as science. Rarely can that have been better exemplified by Learmonth and his mentor.