A boy killed an eastern European man with a “superman punch” that caused him to fall and hit his head on the ground, a court has heard.

The boy, now 16, who was 15 at the time of the alleged attack and cannot be named for legal reasons, denies the manslaughter of Arkadiusz Jóźwik, 40, from Poland.

Jóźwik was knocked unconscious outside a row of takeaway shops in Harlow, Essex, in August last year, and later died in hospital from head injuries. He had been drinking with two friends and had just bought a pizza when he was set upon.

On Tuesday, Rosina Cottage QC, prosecuting, told Chelmsford crown court: “The prosecution does not say that [the boy] thought for a moment that what he did would result in the death of a man.

“However, we say he moved deliberately around the back of Mr Jóźwik to take him by surprise and to hit him from behind.

“[He] jumped up from the ground, using the whole force of his body to hit Mr Jóźwik to his head. From what looks to be like a ‘superman punch’ that he threw, he must have intended to send the man to the ground.”

The defendant sat with his parents at the back of the courtroom, and the judge, Patricia Lynch, and barristers sat without their wigs and robes due to his age.

Cottage said Jóźwik had been drinking vodka with his friend Radek Koscelski and they were both “speaking loudly and appeared to be drunk and smelled of alcohol”. She said a third friend, Jakub Lusiecki, drank beer and “appeared to be sober”.

The three men sat on a bench near a group of teenagers with bikes, including the defendant, who had been there for most of the day, Cottage said.

The attention of the Polish men was drawn to the group of teenagers, she continued, as “something was kicked or thrown close to them” in the Stow shopping precinct.

“There was some laughter about their English and one of the teenagers was cycling around the group,” Cottage said, adding that Koscelski “was swaying and drunk and may have been argumentative, offering to fight”, but made no physical contact.

Cottage said two boys cycled close to Koscelski and Jóźwik, which “seemed to spark a disagreement” between the two groups.

Showing CCTV footage to jurors, she said it appeared that Koscelski tripped over his own feet, then the defendant “appears to jump in the air and swing his arm with force to the head of Mr Jóźwik”. Some members of Jóźwik’s family, who were in court, left the room as the CCTV footage was shown.

Blood alcohol tests on Jóźwik showed he was around “twice over the legal limit to drive”, Cottage said. “Mr Koscelski was clearly very drunk and the deceased Mr Jóźwik was also drunk, but the prosecution says there was no need for violence to be offered to either man. We say he was not aggressive to the group and certainly not [the defendant].

“For whatever reason, maybe even just immature bravado, the prosecution say [he] took a deliberate decision to use unlawful violence when he went around the back of the group to punch Mr Jóźwik.”

In a police video interview shown to the jury, a teenage boy who was in the group with the defendant on the night said two Polish men approached them. “Both of them were saying ‘Fight me’,” he said. Asked by the detective how he felt when they came over, the boy replied: “I felt scared because they were quite big and tall. I didn’t know why they came over asking for a fight.”

Asked if he heard any comments made about the Polish language, he replied: “No.”

Further asked if he had heard any derogatory comments about the men based on them being Polish, he said he was not aware of any.

The trial continues.