A boy nearly killed his best friend by plunging a knife into his shoulder at a party, apparently over a girl.

Croydon Youth Court heard the 17-year-old, who can not be named for legal reasons, left his childhood friend fighting for his life after stabbing him so hard the blade went through his shoulder and came out of his back.

The excuse he gave police was that the victim had "pushed his ex-girlfriend."

The 17-year-old, who pleaded guilty to wounding or inflicting grievous bodily harm without intent days after the incident, was sentenced on Tuesday to a 14 month detention and training order.

The friends had arrived together at a party in Devonshire Road, Sutton in March this year.

After drinking seven to eight cans of cider, the attacker had got into a row with the owner of the property, whose daughter was hosting the party.

Prosecuting, John Shepherd, told the court: "[the defendant] became argumentative, and [the victim]stepped in but he failed to listen to wise counsel.

Suddenly things got completely out of control. [The defendent] picked up a kitchen knife, waved it around and stabbed [the victim] in the shoulder with it."

The victim stumbled outside of the block of flats, before telling a friend "I need an ambulance".

Mr Shepherd said: "I shudder to thing what might have happened if nobody was there to help."

The court heard on Tuesday, May 14, how the assailant cradled his friend's head as he lay bleeding on the floor and the ambulance arrived.

Mr Shepherd added: "When he got to hospital, surgeons took him straight through to theatre as it was a life or death situation."

A victim impact statement read out in court from the victims mother said how difficult it was seeing her child on a life support machine.

Mr Shepherd said: "He wanted to be a labourer, but now he can't, his mum says he cannot open a bottle of juice."

Defending, Henry Oghoetuoma, said: "The events of that day were tragic, we could be dealing with a loss of life, but the friend, who [the victim] still loves dearly, is thankfully still alive."

Chairman of the bench, Derek Richards, told the defendant: "Everyone agrees on the tragedy of this.

"We are obliged to take into account the impact statement from a life long friend of his.

"He is obviously remorseful however alcohol is no excuse, the seriousness of the injury was potentially life threatening and we feel detention is appropriate."