A group of 25 young people, mainly boys, with maybe four teenage girls, is huddled against the long wall of a cheap hotel on a downtown Durban side street. Old chairs and abandoned crates comprise their makeshift furniture, ragged blankets and stained sleeping bags their only warmth. A few sniff glue from plastic bottles. A sign hanging above them reads: “Daily accommodation, open 24 hours.”

For these youngsters, there is no accommodation, at any hour, and the arrival of a cohort of British holidaymakers, including children as young as seven, initially creates a slightly surreal setting, with just a hint of anxiety from the visitors. It’s football that breaks the ice.

Evan, my 11-year-old, gets into conversation with two boys who are optimistically wondering if he might part with his trainers. They don’t appear to have any shoes, but the lingua footballistica of Beckham, Owen and Rooney is one we can instantly share. Within minutes, we are hearing how children as young as eight end up as homeless urban beggars.

“I did go home once,” explains Tabiso, who was 14 when his mother told him she couldn’t afford to keep him. “But there was no place for me, so I came back, because all my friends are here now.” Not quite all of them. Some have died, victims of HIV/Aids or casual violence, but Tabiso is putting his hope in the person leading our unusual summer holiday from the UK.

“Tom,” he says confidently, “is going to teach me to surf, and that will be the job that will get me off the streets.”

He’s talking about Tom Hewitt, who was a young surfer from Surrey when he was drawn to Durban, 15 years ago, for its year-round rideable waves. He was so struck by finding children abandoned to the streets that he stayed to help. He never came back and, with his wife, Mandi, herself a former street child, he has founded a small organisation, Umthombo, supported by a London-based human-rights organisation, the Amos Trust. Every year, it successfully reintegrates children with their families or helps them into education and work.

In an innovative bid to harness the tourist appeal of South Africa to promote awareness of these children, it now customises a beach and safari holiday to include an experience many visitors miss – the South Africa of shantytowns and street kids.

It was Tom and members of Umthombo’s staff, many former street children, who met our four-family party of 19 at Durban airport, loaded our bags onto their vans and drove us to our self-catering apartments, overlooking the yellow curve of Durban beach and the azure span of the Indian Ocean.

The apartments featured bedrooms clustered around a large kitchen/living space for cooking, but we soon realised the local food is so good – especially the fish – and the restaurants so cheap that eating out would be more fun. It’s no secret that Durban has some way to go before it can rival Cape Town as a tourist attraction, but it’s warm all year – and so is the ocean.

Despite flying from British summer to South African winter, we were in the sea within hours of landing – stopping only for a pep talk on personal safety. The downside of Durban is its reputation for street crime and violence, but over two weeks, our group didn’t experience any trouble. That said, vigilance was the order of every day, and one of the four dads always travelled in our different groups, to beach, restaurant or shops.

We had embarked on this unusual family holiday in a slightly risky bid to experience the natural beauty of Africa without ignoring its unnatural poverty. Chris Rose, from the Amos Trust, led our party, working with local guides to create an itinerary designed to help us see not just the poverty in which street children live, but the causes behind it. In a fine balancing act, he also ensured our trip remained a holiday, rather than becoming a dull fact-finding visit.

A daily pattern developed, involving activities with the street kids, followed by lunch at the fine Beach Café, a short stroll down the promenade, then a few hours on sand and in surf. Sometimes, the contrasting elements of the trip were stark: a day trip to a shantytown on the edge of the city brought us face to face with people consigned to life in the crumbling settlements.

“It’s only when you see those dark shacks, with a couple of toilets for several thousand people, that you start to understand why kids would leave for the streets,” said Alice, my 16-year-old niece.

Another visit took us to a bustling township, where black communities are building sustainable lives in the postapartheid era. Eugene, our host, recalled life dodging arrest under apartheid, but now faces another challenge. As he cooked a barbecue for us under a starlit sky, and our kids learnt songs from his kids, it dawned on us that he seemed to have rather too many offspring. It turned out that he and his wife are helping raise a dozen children orphaned by Aids.

Most nights, at the hotel, Chris or Tom helped us to talk through the occasionally troubling experiences of the day. Sharing stories in a group, with eight adults and 10 children aged between 7 and 16, proved a powerful way of reflecting and reacting.

At the end of the week, we set off up the coast on the four-hour drive to the Greater St Lucia Wetland Park and a four-day safari, based in the small town of St Lucia. With geckos climbing the walls, monkeys on the roof and a slightly confused baby hippo wandering down the street, this was a world away from urban Durban – and perfect timing. We stayed in small apartments, with an outdoor pool a few hundred yards from the crocodile-infested river.

In the game reserve, we discovered wild Africa, rubbernecking giraffes, rhinos, zebras and lions in the distance. When our vehicles became separated, only half of us bumped into a 60-strong herd of elephants by the riverside – a sight even our guide said was rare. The rest of us overcame our disappointment on the remote and pristine beaches – empty of tourists and development, and home to sensational waves.

The highlights of our return to the city were early-morning whale-spotting and a beach football match-cum-barbecue with the street kids. “We were cheering each other on, laughing at missed shots and trippings-up,” my daughter Grace, 14, wrote in her diary. “I was with some of the most underprivileged children in the world and some of my best friends. Surreal and exciting at the same time.”

It would be a mistake to romanticise this trip; for adults as much as children, it can be a shocking experience to see first-hand the poverty of so many people in the world. But it was inspiring to see how one small organisation can help children to find a new life.

The sea, sun and safari were as memorable as you’d expect in South Africa, but my guess is that encountering these children is what will stay with us through the rest of our lives.

Further information: the Amos Trust (020 7588 2638, www.amostrust.org) runs trips to Palestine/Israel, Nicaragua, India and South Africa. An 11-day trip starts at £1,500pp, including time at the local project, flights from London, accommodation and sightseeing.

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