On a conference call it’s difficult to tell who’s who.

Yet for all their competitiveness as siblings and in their sporting life, 25-year-old Alistair, the older of the Brownlee brothers, appears to let his 23-year-old brother Jonny take the reins.

“He is always telling me what to do but I am standing up for myself a little bit more now!” laughs Jonny.

As professional athletes they train together. Competing has become their life, and they support each other equally, sharing in their achievements and disappointments. It’s something most siblings do, like squabbling.

By the nature of their profession there is bound to be rivalry but being brothers the rivalry existed long before they took up athletics.

“We used to be competitive at everything – table tennis, board games. We’d fall out over Monopoly and would start throwing houses at each other!” says Alistair.

“I think competitiveness is a crucial quality to have. It is what drives people and drive is really, really important. You may want to try to make your life the best it can be or do as well as you can at work, be as healthy as you can, all that is important and competitiveness stems from that.”

It was Alistair, who received an MBE along with all the rest of Team GB’s gold medal-winning Olympic and Paralympic athletes, who introduced his brother to the triathlon, the event the Brownlee brothers have become famous for after successfully competing in the London 2012 Olympics. Alistair was the winning triathlete while Jonny took the bronze medal.

“When we were little, I was six and he was eight, I used to follow him around. I saw him doing triathlon and thought it was amazing and a cool sport. And the first day at school I was really nervous but he looked after me and if I was ill he told the teachers,” says Jonny.

Both boys pursued sport as a profession and sharing experiences is something they relish – the greatest being the Olympics.

“It was great to go through the good times and the hard times – being stood at the start of the Olympic Games having a joke and a laugh.”

For some athletes, competing and winning in the Olympics can be the pinnacle of their career – but not for the Brownlees who are currently training hard for next year’s Commonwealth Games and the Olympics in Rio de Janeiro in 2016.

“We are training really hard, about 35 hours a week and it is training hard,” says Alistair.

Growing up in Horsforth, the boys recall spending time den building in Hunger Hills, an ancient woodland close to their home village.

They say their parents encouraged them to explore the great outdoors through activities such as walking. “We do appreciate it now and we like to train outside. Yorkshire is a great place to do that.

“We had a great childhood and could quickly get into the woods, climbing trees at Hunger Hills, sledging in winter, playing cricket and football. We were very active and we enjoyed being outside.”

Experiencing the pleasures of being out in the great outdoors has inspired the lads to become ambassadors for Warburtons’ Half & Half range, which launches during the October half-term.

By creating a fun-packed scrapbook, inspired by their own childhood memories of school holidays and time-honoured rivalry, the lads hope to inspire youngsters to keep active in the great outdoors this half-term.

The scrapbook also features short videos of the boys going head to head in childhood pursuits such as mini trike racing and mascot bungee running.

Increasing levels of childhood obesity and fears of youngsters leading couch potato lifestyles could lead to a lazy generation.

But according to the Brownlee brothers, everyone is responsible for encouraging children to be active. “It is so easy to get out there. I remember throwing stones against a tree, building dens,” says Jonny.

The brothers’ half-term tips include an Olympic-themed assault course as well as traditional favourites such as den-building and tug of war.

Other boredom busters include tiddlywinks, treasure hunts, an indoors obstacles course and the sports day favourite egg-and-spoon race.

“This campaign is everything we are about. It is about competitiveness in youngsters, getting people outside and active, which is what we are absolutely passionate about because it has such a massive impact,” says Jonny.

Check out the Brownlee brothers’ Half & Half scrapbook at facebook.com/warburtons for some half-term activity inspiration.

The brothers gave an insight into their sporting life when they spoke about their book Swim, Bike, Run revealing their triathlon story, at the Ilkley Literature Festival on Saturday.