A man has been found guilty of murdering a teenager after refusing to let him into a party.

Jemal Williams, 20, of Berkeley Gardens, Winchmore Hill, was convicted of chasing 17-year-old Shaquan Sammy-Plummer down the street before stabbing him in the heart.

Williams fled the scene, but eventually handed himself in and was found guilty of murder.

Detective Chief Inspector Jamie Piscopo of the Metropolitan Police called the death “a meaningless tragedy.”

He said: “Even when he was turned away from the party, Shaquan made no fuss and was in the process of leaving when Williams decided he needed to teach him a lesson.

"This has been a complex and lengthy investigation with an overwhelming wall of silence preventing us from bringing Williams to justice sooner.

“We understand people might be scared to come forward but we will do everything we can to offer reassurance and support and ensure dangerous men like Williams are dealt with as they should be and families like Shaquan's can be given some closure."

At 9.30pm on January 20, 2015, Mr Sammy-Plummer, of Islington, arrived at a party at Williams' home with two friends, having been invited by the boyfriend of the defendant's sister.

Williams refused to let them in and demanded he hand over a bag containing drinks and snacks they had brought.

When Mr Sammy-Plummer refused and began to walk away, Williams ran after him and stabbed him once in the heart.

Despite neighbours on Berkeley Gardens trying to help and being taken by paramedics to Royal London Hospital, he died.

Williams escaped despite being chased by a friend of Mr Sammy-Plummer, but eventually handed himself in to police on February 9 2015.

In October after he was finally named as the killer by a witness, and despite claiming during his trial Mr Sammy-Plummer had threatened him with a knife, Williams was found guilty.

He will be sentenced tomorrow (April 26).