A court in London has sentenced a British couple to six years behind the bars for keeping a Nigerian immigrant as a slave for nearly 25 years.

Emmanuel Edet, 61, and Antan Edet, 58 have already been found guilty of child cruelty, slavery and assisting in illegal immigration.

They brought Nigerian man to Britain in 1989 when he was 14 years old and forced him to work long hours for no pay.

The couple had apparently changed the victim’s name and added him to their family passport as their son.

According to prosecutors, the couple had promised to educate and pay the teenager. But later on, they threatened him with deportation if he tried to run away.

They forced him to cook, clean, garden and care for their children for some 17 hours a day.

“He believed this and felt trapped and completely dependent on the Edets…Emanuel and Antan Edet have cruelly robbed this victim of 24 years of his life. They have treated him with complete contempt…This was a shocking case of modern day slavery,” Prosecutor Damaris Lakin said on Monday.