The six-year-old boy who was allegedly thrown from a viewing platform at Tate Modern has suffered brain injuries, broken arms and legs, and a fractured spine, a court heard today.

The youngster, a French national who was visiting London with his family, plunged around 100ft in the horror fall on Sunday afternoon while visiting the world-famous gallery with his parents.

Prosecutor Sian Morgan told the court the boy survived the fall after landing on a fifth floor roof, but has suffered a “deep bleed to the brain”.

“He suffered very serious injuries and is currently in hospital”, she said. “He has injuries to his brain, and fractures to his spine, legs and arms”.

A 17-year-old, who cannot be named due to his age, appeared at Bromley Youth Court accused of attempted murder this morning.

He was sporting a bruised right eye as he stood in the dock in a grey tracksuit to confirm his name, age, address, and British nationality.

“This is an incident which took place on August 4, the complainant is a six-year-old boy who was visiting the Tate Modern gallery with his parents”, said Ms Morgan.

“They were on the tenth floor viewing platform, looking over the side, and enjoying the view.

“The six-year-old started to walk a couple of feet away from his parents.”

She said the teenager is accused of picking up the boy and throwing him over the edge of the viewing platform “extremely swiftly and in one movement”.

The boy was airlifted to hospital as staff locked down the gallery, and police arrived to detain the suspect.

Olga Malehevska, who was on the viewing platform with her four-year-old son when the incident took place, described it as “absolutely terrifying”.

Appealing for witnesses, Detective Chief Inspector John Massey said: “It would have been incredibly distressing to watch, and it may be that you left Tate Modern very quickly after. If you have not yet spoken to us about what you saw, please contact us without delay.”

Witnesses reported in the aftermath seeing the boy’s distraught mother calling out “my son, my son” and desperately trying to climb over the barrier after him, before being restrained.

Scotland Yard said there was nothing to suggest the victim and the teenager accused of carrying out the attack were known to each other.

The youth from northwest London, has not yet entered a plea to the charge of attempted murder. A formal plea hearing has been scheduled for August 22.

He was remanded into a youth detention by magistrates David Armitage and Esther Amanang, until a hearing at the Old Bailey on Thursday to consider bail.

Anyone with information is asked to call Crimestoppers anonymously on 0800 555 111.