The father of a grammar school pupil stabbed in March shouted “where is the justice for my son” and collapsed in court, as two teenagers on trial were cleared of his son’s murder.A 17-year-old boy has been found not guilty of the murder of grammar school pupil Yousef Makki, 17, who was stabbed in the heart with a flick-knife in Cheshire.He was also cleared of an alternative charge of manslaughter. As the jury’s verdicts were delivered, Yousef’s father, Ghaleb, stood in Manchester Crown Court’s public gallery and swore at the defendants, as other family members wept.Grammar school student Yousef was stabbed in the heart with a flick knife on a tree-lined street in leafy Hale Barns, an upmarket village, in March.The bright A* student was found slumped against a tree on Gorse Bank Road in the suburb near Altrincham.The jury heard that the death was an “accident waiting to happen” after two the 17-year-old boys on trial indulged in “idiotic fantasies”.The young victim had won a scholarship to prestigious £12,000-a-year Manchester Grammar School, the UK’s largest independent day school for boys.The defendant, Boy A, and another boy, 17, Boy B, both from wealthy Cheshire families, were cleared of all charges following a four-week trial at Manchester Crown Court. Both were also cleared of conspiracy to commit robbery in the lead up to Yousef’s death. Despite the privileged backgrounds of the defendants, they spoke and acted like “middle-class gangsters”, the court heard.Neither of the two defendants can be named because they are under 18. Pupils consoled each other outside Manchester Grammar School in March whilst paying tribute to Yousef MakkiCredit:Mercury Press & Media In his closing speech to the jury, Alastair Webster QC, defending Boy A, said the “silliness” shown in the social media videos shared by the boys showed the stabbing was an “accident waiting to happen”.He added: “Juvenile gangsters playing around with knives. What’s going on with a whole generation of children with the advantage of good families and good education?”They appear to have led double lives, living out idiotic fantasies. Talking in stupid jive talk. Idiotic, juvenile, pathetic, but not sinister – stupid.”Police were first alerted around 6.40pm on Saturday March 2 to reports a teenager had been stabbed.Officers attended the scene and Yousef was taken to hospital, where he died a short time later.Boy A denied murder on March 2, claiming he acted in self-defence.He admitted perverting the course of justice by lying to police and possession of a flick knife.Boy B, was cleared of perverting the course of justice by allegedly lying to police about what he had seen but also admitted possession of a flick knife. Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings.