From Monday to Friday, Osezua Osolase filled his pay packet working on the conveyor belt at his local recycling plant. He made his fortune at the weekend operating another one.

After clocking off, the former security guard criss-crossed Europe on budget airlines escorting teenage girls - cowed into silence through juju witchcraft rituals and extreme sexual violence - to sell them into the continental sex trade.

Osolase, 42, was last night facing a long prison term after a jury convicted him of bringing impoverished young Nigerian girls to Britain before selling them on for up to 70,000 euros a time to continental gangs.

Police identified flight records, mobile phones and pre-paid credit cards to show that he recruited 28 girls and escorted many of them abroad over a 15-month period from 2010 in a scam that could have netted him around £1.5 million.

But Osolase boasted to one of his victims that he had been running the scam for more than a decade from his modest home in Northfleet, Kent.

The 42-year-old ensured the girls’ obedience by using rape as a weapon and binding the young girls to him with “juju” rituals – a powerful force in large parts of Nigeria - that left girls fearing death if they ran away or spoke up against him.

One of Osolase’s victims told how she was taken to a house of witchcraft in Lagos before she was brought to Britain for a promised education that she never received. The teenager was handed a mixture consisting of what appeared to be blood and cloth and told to bathe in it and wrap the cloth around her. A priest cut hair from her armpits, some of her finger and toenails and extracted blood from her hand.

Removing body parts meant that they could be controlled from afar. Another teenager said the woman was told that the body parts taken in the ritual would be used to find and kill her if ever she tried to run away or spoke out against him.

But in a major breakthrough for police, officers traced three of their victims – aged 14, 16, and 17 – who were prepared to speak out against him after they were stopped while travelling to the European cities on false travel documents.

The case highlighted the wider problem of sex trafficking from Nigeria, identified by the Serious Organised Crime Agency as the biggest source of all child sex-trafficking victims from outside of Britain with thousands of girls transported by land and air into Europe. But the vow of silence – and fear that they could be magically harmed - means that the true scale of the abuse remains hidden.

“This case has given the victims a chance to tell their harrowing stories and be believed. They are talking for at least 25 other nameless and faceless victims who are now living lives of prostitution in Europe,” said Detective Inspector Eddie Fox, who led the investigation.

“There are thousands of girls being moved around the world by organised crime gangs and this is just the tip of the iceberg.”

Osolase deliberately targeted some of the most vulnerable girls in the world – orphaned, ill-educated and homeless – and brought them to Britain where he kept many of them in captivity.

One of the girls, aged 16, was living under a bridge before she was approached on the street by Osolase. He promised her an education but when she arrived in Britain, she overheard him trying to sell her for up to 70,000 euros.

She was then told that she would be sent to Italy. “I begged him. I said that I had been suffering in Nigeria for what I had already been made to do.”

The majority of Osolase’s victims were trafficked to Italy, Spain and France where there is a high demand for West African women to work in the sex trade, police said. However, detectives believe that he funnelled his wealth back to Nigeria and had no trappings of wealth at his home in Kent.

Kent police said Osolase’s web was “global” working with contacts in Nigeria and gangs in Europe to take the girls to their final destination. His contacts in Nigeria and continental Europe have not been identified.

Debbie Ariyo, the founder of Africans Unite Against Child Abuse, said that traffickers often worked in small groups with family members and friends spread across Europe.

“We’re talking about small groups who have been able to perfect their trade and beat the system because the system has not been able to respond appropriately,” said Ms Ariyo.

The first European audit of Britain’s anti-trafficking efforts found earlier this year that there were too few specialised anti-trafficking police units and prosecutors across the country to deal with the crime.

Osolase first came to the attention of the authorities in 2007 when he was thrown out of the country for credit card fraud but was able to return the following year after his marriage to a German woman. The court heard he had a double life and had a child with a Nigerian woman in Britain.

Osolase was convicted for five counts of trafficking, one count of rape and one charge of sexual activity with a child. He was cleared of six charges including rape.

Juju: Power to silence

The ancient power of juju witchcraft rituals in west and southern Africa has been manipulated by a new generation of entrepreneurial high priests to fuel the trade in human trafficking, according to experts.

Oath taking and rituals are a major part of juju – a powerful belief system that underpins the world view of millions of west Africans – and are used by the traffickers to ensure the continued silence of their victims.

Rituals typically include the taking of blood, hair and clothing and include swearing oaths to gods who have the power of life and death if the girls breach vows of silence. In one case, a girl was put inside a coffin during a ceremony.

Another girl was told that she would never have children if she revealed who brought her to the United Kingdom.

The bodily parts are invested with a power following the ritual, giving their holders control over their now subservient charges.

“It was very brave of the young women to speak out,” said Dr Hermione Harris, an expert in juju, who gave evidence at the trial. “If they begin to feel a bit ill or have a cold they begin to feel the curse is beginning to work.”

The juju system of magic is most closely associated with trafficking in the Kenyan state of Endo, which has historical trade routes with Italy. With the decline of leather and other trades, sex trafficking filled the void.