A girl of 11 told a court of her “nightmare” as she was forced to watch her brother being tortured to death by a couple who believed he was a witch.

Kristy Bamu, 15, was visiting London from France for a Christmas holiday with his siblings.

The girl said the children were starved and allowed to only drink water at the home of defendants Magalie Bamu and Eric Bikubi in Hathaway Crescent, Manor Park.

Kristy, Magalie’s brother, was found dead on Christmas Day 2010.

The girl, who cannot be named, told the Old Bailey Bikubi beat her with a stick bigger than she was.

“Eric hit me with that on my arms and on my head,” she said.

The girl said she was forced to take part in a bizarre ritual with a light bulb.

“He had a light bulb in my mouth. Then he placed the knife on me,” she said. “He said: ‘Do you know what death is?’”

She said the bulb was also placed in her siblings’ mouths.

Her sister Kelly, 21, was then made to attack Kristy with a pair of pliers, she said.

The court has been told that Magalie Bamu was also part of the violence.

The girl said, as her brother knelt in the lounge, Bikubi smashed ceramic floor tiles over his head.

“Kristy was on the floor and there were spots of blood everywhere. I thought it was a nightmare.”

The girl told the court Bikubi made her mop up the blood with her clothes and Kristy was then taken to the bath and plunged into ice cold water.

“I could see the water was up to his head and he wasn’t breathing any more.”

The girl told the court Bikubi made her get into the bath with her older brother and Kelly. Bikubi then pulled Kristy out of the bath.

Magalie Bamu and Bikubi, both aged 28, deny murder.

Magalie Bamu denies two charges of causing actual bodily harm.

Bikubi has admitted manslaughter on the grounds of diminished responsibility.

He has admitted causing actual bodily harm to Kelly and her younger sister. The trial continues.