AS millionaire Duncan Bannatyne stepped down into the stale sewer caverns of Medellin, in Colombia, he could immediately sense the movement of children finding their way in the pitch darkness.

Without a light at first, he could only imagine what horrors lay around his feet and then, as a torch flashed around the sewers, eleven pairs of innocent eyes were looking his way.

The stale, damp walls are all these abandoned children have to call home, their beds are sodden, dirty mattresses that are littered on the floor and their daily lives are driven by begging and scrounging.

Their world of utter poverty and daily starvation is alien to most in the western world and, while their story may touch people's hearts, it is a rare few who make it their duty to help.

Bannatyne, 54, one of the North-East's richest men, is one such saviour. He has pledged thousands of pounds towards building a safe house in the town after being profoundly affected by the plight of abandoned children.

On his recent visit to Medellin, he experienced first-hand the terrifying reality of how these children are stripped of their youth and forced on the streets from an early age. Heart-wrenching images of small children begging on the sides of dirty roads and kids stealing left-over scraps of food will remain with him forever.

Recalling his journey into the blackness of the underground sewers, he says the experience was, at first, very frightening.

"I was scared - I didn't know what to expect. It was pitch black and yet I could feel people moving about around me," he says.

Helped by an interpreter and guided by a local girl, who had once lived on the streets, he was able to communicate with the sewer dwellers.

"There were ten boys and one girl. The girl, a teenager, made it immediately clear to me that, despite there being so many males, only one was her boyfriend," he recalls.

"She told me, with some pride, that she 'had child'. What she meant is that she had given birth, but that baby was abandoned at the hospital straight away.

"These children living in the sewers, sleeping on dirty mattresses, have no identity. They are not registered, they don't even know who they are, so they can't get a passport, driving licence or a job. As far as the state is concerned they don't even exist."

Poverty, violence and a lack of work opportunities have taken their toll on children throughout Colombia. An estimated 2.7 million of the country's children are forced into the labour market, earning as little as 13 per cent of the minimum wage, while others try to earn a living on the streets - washing car windows, selling cigarettes or committing small thefts.

"It is strange that in a place like Medellin where there is such poverty, there is a MacDonald's on almost every street corner," Bannatyne says.

"Children sit outside the restaurants looking in. If you eat there and leave some food - maybe some chips or a bit of drink - the youngsters will rush in once you have gone.

"They will quickly eat the chips and have the drink, then dash out again before the management catches them. They are desperate for food."

Medellin is Colombia's most violent and dangerous city, made infamous in the 1980s and 1990s by the Medellin drugs cartel. Street fighting is not unusual, with constant battles between the bandas (youth groups) and various parliamentary groups.

The unrest and poverty results in many children being abandoned, some just hours after they are born, or leaving their families after suffering emotional, physical or sexual abuse. These "street children", as they are known, are then forced to survive alone.

Bannatyne was approached by Scottish International Relief (SIR) to fund a project to help street children under the age of eight. At first he was unsure of the scheme, but as soon as he saw for himself the horrific conditions these children are living in, he agreed.

In May, the fitness clubs boss bought a large, old property in Medellin for £150,000, which will be converted into a home for about 24 street children. The safe haven, due to open in September, will have basic living facilities.

"We want to get these young children off the streets before they become acclimatised to living there," says Bannatyne. "When I was over there I found that the older children prefer to live in the sewers because that is what they are used to.

"We are hoping that the home will also provide some day care for other children on the streets. It will have only basic facilities by our standards, but it will be clean and safe and that is the most important thing."

Last year Bannatyne worked alongside SIR, pledging £100,000 towards the building of a Romanian orphanage for abandoned children in Transylvania. The youngsters, all infected with Aids or HIV, were rescued from a state-run hospital and taken into the orphanage, which recently changed its status to a hospice.

The hospice, which now houses 24 youngsters in three blocks, has gone from strength to strength, feeding, housing, educating and restoring hope in children who were once living in appalling conditions.

Bannatyne, a father-of-six, travels to poverty-stricken places in Romania, Africa and Colombia, about three times a year with SIR director Magnus MacFarlane-Barrow. He says the images of children living in sewers and on waste tips have had a profound effect on him.

"I think I want to be able to help because I know I can do it financially and it is a challenge. These children don't know what a toy is and have never had a cuddle. We are giving them a chance to have these things but what they really need is some money to enable them to get an education and have a chance of a better future."