A Nigerian couple in London who enslaved a man for almost a quarter of a century were on Monday jailed for a total of 12 years.

Doctor Emmanuel Edet, 61 and his wife Antan, 58, were sentenced for slavery, child cruelty and assisting unlawful immigration.

They took the victim from his home country, Nigeria, to the UK without his family’s permission in 1989, when he was 13 years old.

He agreed to be their “house boy” on the basis that he would be paid and receive schooling, but they made him carry out arduous, unpaid labour for 24 years.

He was forced to work for around 17 hours every day at their homes in Chatham, Scarborough, Walsall, Northolt and later Perivale, West London.

The Edets kept notes on the standard of his work, which included rigorous cleaning, caring for their two children and cooking for the family.

They controlled every aspect of his life, from what he could wear to when he could leave the house, and demanded that he only spoke to them in Nigerian but to the other children solely in English.

They claimed they had adopted him as their son but in reality they forbade him from even eating in the same room as family members.

He was not allowed to enter most of the rooms in the house unless it was to clean them, and they made him sleep on a dirty piece of foam on the hallway floor.

They verbally abused him, calling him a “parasite”, and convinced him that if he went to the police, he would be arrested for being an illegal immigrant.

The Edets controlled the victim so effectively that even when they left him alone in the house for weeks at a time, he did not run away.

In December 2013, the Edets returned to Nigeria for Christmas, leaving the victim alone at their home in Perivale for several weeks. Before leaving, they set up a remotely controlled CCTV camera in the hallway so they could monitor him.

The victim, having recently seen media reports about modern slavery, realised the life he was being made to lead was wrong and emailed the charity “Hope for Justice” from a computer at the house.

Hope for Justice referred the matter to the MPS Trafficking and Kidnap Unit on 19 December, and the next day detectives helped him leave and get specialist support.

The unit carried out a lengthy investigation, including a number of sensitive interviews with the victim. They subsequently arrested and charged the Edets on 6 March, 2014.

Detective Chief Inspector Phil Brewer of the Trafficking and Kidnap Unit, said: “The Edets took self-appointed ownership of the victim. They controlled what he wore, what he did and how he spoke for the majority of his life.

“When the victim left Nigeria, he was a young boy with aspirations but the Edets abused him until he became timid, nervous and obedient.

“Today the victim is living a new life in the UK. He has a job, a home with his own bed and freedom to move, and he is studying.

“While he will never fully overcome what happened during those 24 years, he is determined to make the most of the rest of his life and today’s conviction will help him feel he can do that. In his own words, he has hope and a future now.”

•Adapted from The Sun (London). Photo shows the convicted Doctor Emmanuel Edet and his wife Antan.