The sentencing hearing of 18-year-old Jonty Bravery has begun at the Old Bailey.
Bravery, from Ealing in west London, admitted attempted murder when he hurled a six-year-old boy – who cannot be named because of his age – from the viewing gantry of the Tate Modern in central London on August 4 last year.
The boy, on holiday in London from France with his family, suffered life-changing injuries.
Bravery appeared via video link wearing a white T-shirt and dark shorts.
At the start of the hearing Bravery entered, through his counsel Philippa McAtasney QC, five not-guilty pleas to an outstanding matter.
None of the charges were read in court, although the prosecutor Deanna Heer said the principal charge was for racially aggravated common assault.
Ms Heer said the prosecution, at the end of sentence for attempted murder, would ask for the charges to lie on file.
Prosecutor Ms Heer told the court Bravery was a “looked-after child” under the care of Hammersmith and Fulham Social Services at the time of the incident.
He was living in supported accommodation and had autism, she said.
He received specialist care following an assault on a female care worker in October 2017, but was “frequently aggressive to staff”.
He was also abusive and failed comply with boundaries.
He lashed out at staff every “six weeks or so”, she said.
Ms Heer said Bravery was 17 at the time of the attempted murder, on Sunday August 4 2019, and was under one-on-one supervision but was allowed to go out unaccompanied for four-hour periods.
He left his property around midday, bought an Oyster card, and travelled from his accommodation in Northolt to London Bridge, arriving at 1.10pm.
Ms Heer said he went to the Shard and inquired about buying a ticket for the viewing area, but found he did not have enough money.
“He was later to admit that he was asking where the next highest building was,” the court heard.
The court heard Bravery made his way on foot to the Tate Modern, arriving at 2.16pm.
Witnesses said he was “behaving in an unusual way” and was seen to look over the railings near where he would later throw the boy over.
Ms Heer said: “A male matching his description struck up a conversation with a lady called Carole Hunter as she looked at the view.
“He commented to her that it was a long way down and that he had vertigo.
“Ms Hunter thought this was an odd comment and moved away from him.”
Two other witnesses, visiting the tourist attraction with their two sons aged 11 and eight, saw the defendant “smiling at the children”, the court heard.
Ms Heer said the couple felt uneasy until he moved away.
The court heard the victim and his family arrived at the Tate Modern viewing platform at 2.32pm, having spent the day sightseeing and having a picnic by the river.
CCTV then caught Bravery turning towards the victim’s family, with the boy skipping a little way away from his parents.
Ms Heer said: “As (the boy) approached, the defendant scooped him up and, without any hesitation, carried him straight to the railings and threw him over.
“The CCTV footage shows (the boy) falling head-first towards the ground.”
Ms Heer said CCTV also showed the defendant backing away from the railings.
She said: “He can be seen to be smiling, with his arms raised. At one point, he appears to shrug and laugh.
“The footage also captures (the victim’s) parents’ disbelief and rising panic at what had just happened.”
She said the boy’s father initially thought the incident was “a joke” until he saw his son’s distorted body below.
Challenged by the father, Bravery said: “Yes, I am mad,” the prosecutor said.
The court was told Bravery “laughed” when he was shown the CCTV of the incident.
Ms Heer said: “He said he wanted to be on the news so that everyone, especially his parents, could see what a mistake they had made by not putting him in hospital.”
Ms Heer said Bravery had conducted a variety of searches including, “Are you guaranteed to escape prison if you have autism?”, “What are the chances of death if you push into the River Thames?” and a web page entitled “How to get away with rape.”