Harrison imprisoned both girls - aged 14 and 16 - at his home in Albert Square, Stratford, in 2009, before attempting to traffic them to Spain and Greece as prostitutes.

The two had been controlled by Juju magic rituals, the court was told.

The case is thought to be the first of its kind in Europe to involve a prosecution linked to such a practice.

Both girls came from small villages in Edo, Nigeria, and were sold into prostitution with the help of the local Juju priest.

Juju is a significant part of West African culture.

Police said Harrison was a key player in a sophisticated network of West African people traffickers operating in the UK.

After Harrison was convicted, the prosecution told the court: "This has been something of a unique case and ground-breaking. It's the first time there has been a prosecution for trafficking out of the UK.

"It's the first time the Crown has been able to persuade victims of these type of offences to give evidence."

Det Con Andy Desmond, of Metropolitan Police, said: "These young women suffered the most terrifying and degrading ordeal - leaving them emotionally, psychologically and physically traumatised.

"Most cruelly of all, they were brainwashed into believing that if they disobeyed their captors by seeking help, they would die.

"They were also told that if they went to the police for help they would be handed straight back to their captors."

A Home Office spokesman said: "We will seek to deport this individual at the earliest opportunity.

"Our priority will always be to protect the public, and we will seek to remove any foreign national convicted of a serious crime.

"Last year we removed 5,235 foreign criminals from the UK."