DR KEITH BROWNLEE tells a story that sums up the attitude that has made his son, Alistair, the world’s leading triathlete and a hot favourite to win Olympic gold in London next year.

The Dewsbury-born 23-year-old has already been a world champion at junior, Under 23 and senior level and eight days ago dominated the World Championship Series race over the 2012 course in Hyde Park.

Dr Brownlee recalls how at the start of one season, when triathlon was a passionate hobby rather than a way of life, Alistair decided he would improve his running by getting up at 6.30am every day to do a circuit of the local woods around Horsforth, dragging his dad along.

Brownlee senior was less than enthusiastic about the new schedule and would seek out his son’s alarm clock and turn it off. But Alistair was determined and hid the clock, ensuring a valuable training opportunity was not missed.

The rise of the baby-faced swimmer, cyclist and runner has been phenomenal, but even more remarkable is that his closest challenger this season has been his 21-year-old brother Jonny.

With podium places in Hyde Park – Jonny produced a stunning 10 kilometre run to come third – the brothers made themselves near certainties for Olympic spots.

Over the past three years, in World Championship Series races in which at least one of them has competed, there has been only a single occasion where a Brownlee has not been on the podium.

Despite this, Dr Brownlee, who works in the paediatric cystic fibrosis unit at Leeds General Infirmary, admits his primary focus remains simply making sure both sons complete the race in good health.

His worries are understandable. Last year Alistair suffered heat exhaustion during the Hyde Park race and collapsed over the finish line. Mum Cathy, who is also a doctor, jumped over the barriers to be with her son as he was rushed to the medical tent.

“We joke that Alistair came 10th and Cathy came 11th,” Dr Brownlee says. Hot weather makes him nervous, and he began checking the long-range forecast two weeks before this year’s race.

“There are a number of feelings,” said Dr Brownlee. “Immense pride at what each of them are achieving, and there is pride that they’re doing it together.

“But the most overwhelming feeling is relief when they finish intact and without injury. I know how far they’re pushing themselves.

“I’ve ended up in resuscitation tents at least twice with each of them. But I think they’re getting older now and more mature and better suited to Olympic distance. I’m a little bit less anxious than I used to be.”

The most remarkable thing for an outsider is the degree to which each brother thinks about the other, before, during and after each race. They may be competing against each other for the sport’s biggest prizes, but it is very much a team effort.

They live together, along with a couple of friends, in Alistair’s house in the village of Bramhope just outside Leeds and have been taken to the hearts of the pensioners that make up the rest of their street, who are happy to take delivery of bike wheels and invite their young neighbours around for tea.