"Trafficking in human beings" is a phrase guaranteed to cause a sharp intake of breath among listeners from the liberal and affluent and concerned West.
The view of trafficking in Nigeria is somewhat different. In fact, it is seen as an everyday part of West African life.
Children can either be an economic burden or an economic resource
It starts with the promise of a better life.
The parents are taken in. The children are persuaded. When they leave home they do so willingly, with some excitement, not trepidation.
The trafficker has promised a good job, a schooling, a regular income. But that is not how it works out.
One young woman told me she was promised regular work in the Nigerian countryside.
She found herself transported overland through the north of Nigeria, to Mali, then to Algeria, then Morocco.
From there she was smuggled into Spain, at night, in a small boat, and from there, on forged papers, into Italy by train.
They took her to a house in Turin where she lived with other girls, some, but not all, Nigerian like her, and under the control of a madam, also Nigerian.
She was put to work as a prostitute, something she speaks of now with a discernible shame.
After seven months she had earned enough money to pay off what she owed the traffickers for taking her in the first place.
When that debt was paid, her trafficker shopped her to the Italian immigration authorities and she was repatriated, home to Benin City, Nigeria with nothing to show for her ordeal.
The streets of Nigeria are teeming with trafficked children
There was a second young woman with a similar story.
Not yet out of her teens, her traffickers took her to Verona where she worked as a prostitute.
She spoke without shame. She spoke with anger.
"Just when I had paid off my debt," she said. "Just when I was about to start working for myself, the police caught me."
This is the pattern. The traffickers do not want their working girls setting up on their own, taking custom away from their girls.
Turnover - in human traffic - is everything.
Oil rich cities
Unicef estimates that human trafficking is more lucrative than any other trade in West Africa except guns and drugs.
The streets of Nigeria are teeming with trafficked children.
Of the hundreds of thousands of street kids living rough in Nigeria's oil rich cities, perhaps 40% have been bought and sold at some time.
The girls most frequently sold into domestic service, or prostitution, the boys into labour in plantations, or to hawk fruit and vegetables for 12-hours a day in an open air market.
Some work as washers of feet.
In Nigeria children enter the labour market almost as soon as they can lift and carry.
Human trafficking is one of the biggest industries in West Africa
We watched a skinny boy in a dust bowl of a quarry carrying stone blocks on his head ferrying them from where they were cut from the earth to where they were broken down into usable pieces for the construction industry.
He worked here alongside his heavily pregnant mother.
He earned 40p (70 US cents) a day, which his mother used to buy food for her five younger children.
The boy was nine-years-old and he had been working at the quarry since he was seven.
Unicef believe there are 15 million children working in exploitative labour in Nigeria.
It is a 21st century slave trade.
What is most striking is the tacit support that human trafficking enjoys at almost every level of society.
The Lagos middle class have a bountiful supply of house boys and house girls, brought from villages in the north by helpful aunts and uncles who pocket the cash and disappear.
Trafficking has the tacit collaboration of the victims' own families
No-one asks questions. No-one wants to know the answers.
For human trafficking is not something that happens on the criminal fringes of Nigerian society.
It is woven into the fabric of national life.
In Benin City, in the oil rich Edo state, east of Lagos, I met an articulate 15-year-old girl who said many of her friends had been trafficked.
"Their parents are involved," she said. "They say to the girls: 'Why don't you go with this man and work. We have no money, we have nothing to eat. You can send us money.' And so the girls go."
And that is the problem. That trafficking has the tacit collaboration of the victims' own families. That it is not seen as criminal activity at all but as a normal and even respectable way for a family of - say - seven or eight children to boost its meagre income.
I have filmed for BBC television news in many countries of Africa over the last decade. But I have never had an Oscar winning Hollywood movie producer carry my tripod before.
David Puttnam - who made Chariots of Fire, Midnight Express, The Killing Fields - knows a lot about trafficking.
As president of Unicef UK he has seen it across Asia as well as in Africa.
What frustrates him here, in Nigeria, more than the poverty that is its root cause, is the attitude that accompanies it.
"Half of you feels sympathy," he told me.
"But the other half wants just to shake the people here and say look - this is a large, wealthy, powerful country.
"Put the structures in place. Develop some determination. And this exploitation of children could be tackled and Nigeria could be a really successful nation".
From Our Own Correspondent was broadcast on Saturday, 17 April, 2004 at 1130 BST on BBC Radio 4. Please check the programme schedules for World Service transmission times.