A jury has retired to consider its verdict in the trial of a 15-year-old boy accused of murdering a schoolboy who was stabbed in a nature park.

Newcastle Crown Court has heard how Tomasz Oleszak, 14, collapsed soon after the fatal wound was inflicted at a park in Gateshead, last October.

The defendant, who was also 14 at the time of the incident and cannot be identified, denies murder and attempting to cause grievous bodily harm to a different boy whose coat was slashed when trouble flared.

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He has previously admitted carrying a blade.

Mark McKone KC, prosecuting, has told the jury how Tomasz was in a group of youths who followed the defendant as he walked through Whitehills Nature Park with his girlfriend last October.

Mr McKone said: “The prosecution say that (the defendant) took the knife out hoping he could use it to stab someone.”

The victim’s group was not “blameless” and the defendant had faced “hostility”, the barrister said.

But he said the prosecution do not accept he was acting in self-defence when he stabbed Tomasz and slashed the jacket of another boy after being knocked to the ground by the group.

The jury heard how Tomasz was stabbed above the heart, entering his aorta with a wound that was 3.2in (8cm) deep and 1.8in (4.5cm) wide.

The jury was told the defendant told the gang “I have wetted your boy” after Tomasz was stabbed.

Mr McKone said: “He wanted them to know he had stabbed one of their number. It was a boast.”

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Peter Makepeace KC, defending, said his client had not looked for trouble and asked the jury to put themselves in his situation: aged 14, attacked by a group, in the dark, not knowing if any of the gang were armed.

He said: “This is a 14-year-old under group attack and having to make terrible decisions under a moment’s notice.”

Mr Makepeace asked whether the prosecution had made the jury certain that the defendant was not acting in self-defence, and whether jurors were certain that he was not acting without any specific intent to murder.

Th judge, Mr Justice Spencer, completed his summing up on Friday morning before sending the jury out to begin its deliberations.