Kristy Bamu and his two sisters were visiting their older sister, Magalie Bamu, and her partner, Eric Bikubi, over Christmas in London. Initially, it was apparently a jolly time…and then Eric got it into his head that his three visitors were witches.

The court was told that over a period of days the pair, originally from the Democratic Republic of Congo, attempted to exorcise evil spirits they believed were in three of the children – Kristy, his sister Kelly, 20, and their 11-year-old sister, who cannot be named. Bikubi refused "to let them eat, drink or sleep for days, while the punishments became increasingly violent, with [the attackers] using the many implements found in the flat as weapons of torture", Altman said.

During their ordeal the siblings were forced to pray and chant throughout several nights and, in a "staggering act of depravity and cruelty", the defendants recruited sibling against sibling as "vehicles for their violence", said Altman.

Kristy became the focus of Bikubi’s attention, the court heard. He allegedly struck the boy with a hammer in the face, knocking out his teeth; on another occasion he shoved a metal bar into the teenager’s mouth, the court heard.

When Kelly attempted to hit her brother using something light, she was ordered to use a heavier implement. In a desperate attempt to prevent any further suffering, Kristy and his two sisters eventually admitted to being sorcerers, said Altman. "As Kristy’s injuries became ever more severe he even pleaded to be allowed to die," he added.