The villagers of Hlodo know about living with ghosts. The border settlement lies close to the slave coast of Benin, where for more than three centuries their ancestors were led in chains through the Gates of No Return, towards the sound of the sea.

Today, like many other villages in modern West Africa, it is a place where children disappear.

Two hundred years after the transatlantic slave routes were cut off from the nearby port of Ouidah, the village is again caught in an illicit people trade. In Hlodo, where no more than 1,000 people live, dozens of girls have been victims of human trafficking, passed through a cross-border network of extended relatives and gangmasters to be used as cheap labour in quarries, cocoa fields, mines and markets. Most have been traded by their parents in return for false promises of extra income.

Are children still missing? Yes, they say. At least 30.

A man leans back on a chair, tapping a cane over his thighs in the afternoon heat. John Sevi Goka, or “Number one” as he refers to himself, is one of the men who trafficked them. He confidently recites a list of Nigerian destinations where he has “contacts”, and explains that his job is to be the link between supply and demand.

John receives between 1,300 and 2,500 Nigerian naira (£5 to £10) a month for one child’s services, depending on his or her age, strength and the type of work. Satisfied employers will give him bonuses of up to 10,000 West African francs (£10) and his transport costs are deducted from the wages that the child will never see.

“Sometimes people ask why I am travelling with these children. I say he is my brother, my friend, my relative. The children are told what they have to say before we leave, so there is no problem. They know already how it is going to be.”

And if a child asks to go home? “Once we are over the border, I tell them it is not possible. We cannot go back.” As if to underline the point, he adds in English: “Never.”

How many other traffickers does John know in the area? He rolls his eyes and lets out a slow, high-pitched giggle. “Three,” he shrugs. “Maybe four.”

But far from being the local villain, he then returns to join other villagers laughing and joking in the shade of a mango tree.

John’s status comes from the tradition of vidomégon, an age-old practice whereby poor families improve a child’s prospects by “placing” them among the extended family.

At any one time more than 40,000 children are believed to be caught in this cycle of human trafficking in the tiny nation of Benin, where half the population of eight million are under 14.

This Sunday marks the bicentenary of the abolition of the transatlantic slave trade, for which the kingdom of Benin was once a major supplier of “pieces of ebony” in exchange for European weapons.

Less than half the size of the UK, it has since been hailed as a rare example of democratic success in Africa, yet slavery both past and present is never far away.

On the road to Dramé, one of 56 villages in the trafficking hotspot of Zakpota district, you can see a statue of Mother Africa with hands held high above her head and broken chains hanging from her wrists. Near by, in Ouidah, mothers breastfeed their infants while toddlers play among goats and chickens. But children above the age of 6 are few and far between. There is barely a teenage girl to be seen.

“We find ourselves unable to support the children we have,” explains Aisso Adagbe, the chief of Dramé. “When somebody comes from the city — someone well-dressed who has radios and motorbikes, and says ‘Why don’t I take them to a better country so they can send money home to support you?’ it’s difficult to refuse.”

The last time Michel Zomaitohoue saw his daughter Feliciene was four years ago. Like the 15-year-old girl to whom he said goodbye, he believed the fiction of a better life awaiting her on the other side of the border. “She was in her prime,” he says. “She was becoming a woman. I blessed her and wished her success, and she promised me that she would do whatever she could to send money back.”

Feliciene and her 14-year-old cousin, Bernadette, left with Albert Akassounon, a distant brother-in-law, who promised that they would be back within a year. Michel says: “Albert came here and said how well things were going in Nigeria, how he wanted to take the girls out of the path of suffering. He was a very good talker. Only now are we realising it was only talk.”

Bernadette’s mother, Nako Kintohoue Zomaitohoue, is also waiting for the return of her daughter. She has given up on the wages. “What else can I do?” she says. “I have to trust Albert; he is the only contact I have. We believe that she is working in a restaurant but I’m afraid she is sick.

“I have seen other girls and boys come back and I wonder why my daughter isn’t among them. I ask myself if she will survive. It is very painful.”

Local child protection officers know of at least 16 children who have disappeared from Dramé in the past year. They are sure that the real number is higher because parents often lie about their children’s whereabouts.

Gyslain Adagbe is one of the few to have returned. It is a long time before the 16-year-old looks up from the ground, allowing a flicker of eye contact before fixing his stare on his yellow flip-flops.

The first time he saw Seraphine, the local trader, the man was in discussion with his father. The second was three days later, when he came to collect Gyslain for the journey to Nigeria. They left Dramé on a motorbike, hiring a car before reaching the border at night. It was not an official crossing, just a small road. Gyslain, then 13, recalls that Seraphine disappeared for some time. When he returned, they passed quietly through the bush.

“I saw bright lights and I knew I was far away,” he says. “It seemed to be taking so Michel Zomaitohoue, whose daughter Feliciene is missing long. I asked him, ‘Where are you taking me?’ He reached over and touched me and he felt cold. I felt dizzy. I was shivering. The spirits told me that where I was going would not be good.”

His destination was a plantation in western Nigeria. “They told me ‘You will work from here to here’,” he says, drawing a line in the earth. “They said that if I finished I could go home early.”

The little boy never managed to complete his daily tasks. “Seraphine would abuse me. He would tell me I’m a lazy boy. I would cry every day. I threatened to drink poison and die unless I saw my father.”

Eventually, physically shattered, he was discarded and returned home. “When my father saw me he started crying and said it was not meant to be like that,” says Gyslain.

Gyslain says that he has forgiven his father but is determined not to make his own sons and daughters suffer. Finally he looks up with a bitter scowl. “I would rather let them eat sand,” he says. SO LARGE is the problem in Benin that one of the first laws ratified by the country’s new president last year was an antitrafficking bill. But the Beninese police force remains underfunded and overwhelmed, and vidomégon renews its stranglehold on every generation.

Louis Tokpanou, head of the Minor Protection Brigade, the unit responsible for cracking down on child-trafficking, points to a map of West Africa in his office. Benin is obscured by coloured arrows depicting the flow of traffic.

Beige lines, representing the mining industry, flow between Chad and Niger to the north. Green arrows lead to the cocoa fields of Ivory Coast and the cotton plantations of Burkina Faso, while blue lines follow the fishing industry to Togo and Gabon. Black arrows, for domestic servitude, engulf the region.

Benin’s long, unsecured border with Nigeria runs 60km (38 miles) west of the chaos and corruption of Lagos. Inspector Tokpanou says: “We are a source, transit and destination country.”

Norbert Fanou-Ako, the director of ESAM, a local children’s organisation, says it is too soon to be celebrating the abolition of slavery. “Today we are seeing human beings sent to work abroad so that others will profit,” he says. “The conditions are terrible, and as soon as they become too sick or cannot earn money they are discarded. Is that not the same as what happened 200 years ago?”

In the Laura Vicuna Centre in Cotonou, one of many rehabilitation centres supported by Unicef, 113 girls wait for their relatives to be traced. While some giggle and braid each other’s hair, two sit silently in the corner. They arrived yesterday. Aime Dazogbo, 8, has scars all over her back. Xweffa Iboutine, 10, can barely talk.

“I don’t know why I was given to that lady,” whispers Xweffa from behind her hand. “I don’t want to go back.”

She says that she wants to see her father. The problem is, however, that it was her sister who sent her away. CHILD-TRAFFICKING in West Africa also flows along established routes into Europe — including Britain. A study by Ecpat UK, the children’s charities coalition, recently identified 80 suspected trafficking victims in the North West, North East and West Midlands. Of these, 19 were African (most of the others were from China).

Of 84 victims rescued in Operation Pentameter, a series of raids on brothels throughout the UK last year, nine of the 12 underage prostitutes were African, the youngest a 14-year-old found in Dumfries.

In another investigation at Heathrow three years ago, police identified 551 vulnerable children. Most were teenage African girls believed to have been trafficked for domestic servitude or benefit fraud.

The case of Sara Okri shows how far vidomégon can reach. For six years she was locked in the London home of a Nigerian couple and forced to work as an unpaid servant and nanny. “Nobody knew I was in that house,” says Sara, who is now 20 years old. She was 12 when she was sent away by her mother and delivered bya chain of fixers from Lagos to London.

On arrival, her captors outlined her duties: “I wasn’t allowed to touch anything unless I was cleaning. I had to cook them food but wasn’t allowed to eat it. If any of the children hurt themselves, I would be beaten.”

After three years she was finally allowed out to take the children to nursery. “I had to wear a wig and baggy clothes to disguise my age,” she says. “If anyone should ask me anything, they told me, I must smile and walk away.

“I was very lonely. I tried to hang myself but I broke the chair and got beaten for it.”

When accompanying the family to parties, she discovered a hidden community of other trapped nannies. She says: “All the friends also had girls in my situation. When they got together, it made them feel big. Having a girl of your own showed that you had assets. They would shout in front of everyone, ‘Come here, I’m talking to you’. It gave them power.”

Sara (not her real name) claims that the circle included a pastor, but she declines to name him. Even though she is now being supported by social services, she is too scared to press charges.