The Team Sky cyclist is part of an amazing array of talent to hail from a comprehensive in Cardiff

The hall of fame in Wales’s largest comprehensive school is about 15 metres long. Almost every centimetre is covered with carefully framed photographs of current and former students – including Real Madrid footballer Gareth Bale and former Welsh rugby international Sam Warburton – excelling in everything from bowls and shooting to swimming and athletics.

But Whitchurch high school in north Cardiff will have to make space for one more picture if, as expected, another former pupil, Geraint Thomas, crosses the finish line on the Champs-Élysées in Paris on Sunday evening to become the first Welshman and only the third British rider to win cycling’s most prestigious road race since it began in 1903.

His old PE teacher and the school’s longest-serving member of staff, Steve Williams, who coached all three stars, can barely find the words to express his admiration for the quiet, determined boy he taught in the 1990s. “I don’t know where all this is going to stop. It is just incredible,” he says in his small office. “This is really up in the stratosphere of sporting achievement.”

Williams has reserved a place on the wall for another picture of Thomas. “I’d love Geraint to come back to see us after he completes the Tour and there is definitely space for the yellow jersey,” he says.

The teacher – who went to the school in the 1960s and returned to teach there in the 1970s – remembers a shy but bright all-round athlete who had a world of possibilities open up for him at the school. “He competed in all sports. He was a very good athlete, same as Bale and Warburton,” he says. “He did well at A-level. He could have gone to university if he had wanted to.”

Williams says Thomas still has the same beguiling sense of humour. “In his book he says ‘I’d like to thank Mr Williams for not making me play for the senior rugby team’. But I never had any intention of picking him and he never had any intention of playing,” he says, laughing.

Facebook Twitter Pinterest Geraint Thomas on the wall of fame at Whitchurch High School, Cardiff, Wales.

He puts the school’s remarkable success down to its ethos of hard work and a culture that celebrates everyone’s achievements. The comprehensive, which has about 2,400 students, has facilities that would rival a private school, such as two rugby pitches, 10 all-weather football pitches and a swimming pool.

“A lot of private schools use sport as a way of promoting the school as a business. We don’t have any of that – it’s just part of the culture here,” he says. “Whitchurch is a true comprehensive. Our catchment is north Cardiff, but it spreads out into some of the council estates as well.”

This ethos means that there is little swagger in the sporting men and women the school turns out.

“All of them are a breath of fresh air in their chosen sports. Geraint hasn’t had any controversies, apart from falling off his bike a couple of times. The same as Gareth Bale and Sam Warburton and all the others,” Williams says.

In the well-equipped gym, where Warburton still comes to train, two sixth-formers have made an appearance, even though it’s now the summer holidays.

Matt Bennett, 17, says the school’s facilities and its history explain its successes: “When you walk down the hall of fame you see how many people have done well rather than a select one or two on TV – and you think, ‘that could me or one of my friends’.”

As Thomas has inched towards victory in the Tour, Whitchurch’s next generation of cyclists have been following every twist of the race.

Twelve-year-old Jess Hoskins, who rides with one of Thomas’s old teams, Cardiff Just in Front, has been inspired by his sudden rise up the cycling ranks. “He has been a domestique [a supporting rider] for ages in his team and he’s finally taken his chance,” she says.

Eleven-year-old Evelyn Nurse, who starts at the school in September and races in the same cyclocross league, says: “I’m very happy for Geraint – he’s worked so hard. It’s inspired me to knuckle down in my training because I want to be like him when I’m older.”

Both girls are, however, keen that the organisers put on a full women’s Tour de France instead of a few token days. “Women are just as strong as men. It isn’t right,” says Hoskins.

Carl James, who is sipping coffee beside his folded-up Brompton bike, says the growing adulation is the least Thomas deserves after helping Chris Froome win his four Tours.

“Now he is getting his chance for the big time. There is a golden postbox in town for when he won the Olympic gold, so we’ll need to think of something better,” he said.

Star names

Facebook Twitter Pinterest Gareth Bale and Sam Warburton, two more star names to come out of Whitchurch. Photograph: Rex/Shutterstock

Geraint Thomas

Born: 1986

Thomas has enjoyed plenty of success on the track, winning seven world cup titles, three world championships titles and two Olympic gold medals, but has since turned his attention to the road. In 2016 he won the Paris-Nice race riding for Team Sky, and for years he has worked loyally for team leader Chris Froome as he took his four Tour de France victories. Barring disaster, on Sunday he will himself become the first Welshman to win the race.

Sam Warburton

Born: 1988

Warburton captained the Welsh rugby team at the 2011 World Cup, becoming the youngest ever World Cup captain. He led by example, taking Wales to the semi-finals, where they lost to France. Despite the loss, Warburton was universally praised. In 2012 he led Wales to victory at the Six Nations. The following year Warburton became the youngest ever Lions captain, at 24, in their tour to Australia, leading them to their first series win since 1997. He retired earlier this month.

Gareth Bale

Born: 1989

Bale was the second-youngest player to play for Southampton at 16. He moved to Tottenham Hotspur and then to Real Madrid, aged 24, becoming the most expensive player in the world at the time. Madrid have since won the Champions League four times. Bale also took Wales to the semi-finals of Euro 2016.

Jonah Ramchandani