The “tragic and terrible” murder of a 15-year-old outside his school was sparked by gang rivalries, a court has heard.

Four teenagers are accused of stabbing Zac Olumegbon to death outside Park Campus School in West Norwood.

Opening the case against the group at the Old Bailey today, prosecution barrister Ed Brown said that on July 2 they drove up alongside their victim in Gipsy Road before chasing him into a cul-de-sac and stabbing him four times in a gang-related attack. Another teenager was seriously injured in the attack.

Mr Brown said each of the four – who cannot be named for legal reasons – arrived with a knife.

He claimed: “This fact alone gives you a clear picture of what was intended that morning by those who set out to find and attack him... Given the weapons and the determination with which his attackers were acting, once caught there was only likely to be one outcome – that he would receive serious and life-threatening injuries.”

The court heard the attackers were members of Brixton’s Gas (Guns and shanks) gang, while Zac was a member of the rival TN1 (Trust no-one) gang from Tulse Hill.

Mr Brown said: “Zac’s death had its origin in the dreadful but certain fact of rivalry between young gangs in south London.”

He said the four accused had travelled as a team to find Zac and were all responsible for his death, which was “a tragic and terrible waste of a young life”.

All four plead not guilty to Zac’s murder, and three plead not guilty to another charge of wounding with intent – which has already been admitted by the fourth member.

The trial continues.