A teenager accused of murder plunged a knife 15cm into a man and left him to die, a jury was told.

Dominic Adeyemi, 18, is standing trial accused of fatally stabbing Tawana Choruma on December 18 last year.

Choruma, 19, died at the scene of the incident in Netley shortly after he was stabbed.

Opening the case at Southampton Crown Court, prosecutor Sarah Jones KC said three men - Dominic Adeyemi, Tawana Choruma and Jack Hibberd – were embroiled in an row over an unpaid drugs debt.

She told the court Hibberd, who had been charged with murder before his case was dropped by police, owed a significant debt of hundreds of pounds to Adeyemi and he worked with Choruma to try and avoid payment.

"The defendant's frustration can be received through the messages to Mr Hibberd", she said, explaining how Adeyemi tried calling and messaging Hibberd several times prior to Choruma’s death.

The three were due to meet in Netley on December 18 to resolve the debts, but data obtained from Hibberd’s phone revealed he travelled south and “separated from the other two”.

READ MORE: Trial into murder of teenage boy begins - recap

Ms Jones said: “The victim and the defendant are seen later on CCTV walking purposefully towards Mortimer Close, pausing, then going in the other direction back to the recreation ground.

"At 6.21pm the victim calls a friend who is out celebrating his birthday.

"Three minutes later he was fatally stabbed by the defendant who left him to die while he himself fled."

Moments before he fled, passers-by Jennifer Goodhand and Wendy Hislop saw Adeyemi try to pull a man on the ground — Choruma — upwards, before telling the women: “He needs help, get an ambulance.”

In a recorded interview with police the following day, Ms Goodhand said Adeyemi then “disappeared".

Their two friends arrived shortly after, and Jennifer said she saw a "big, long knife lying beside Choruma” which alarmed them.

She added: "I tried to feel for a pulse and see if he was breathing. I was reassuring him that help was coming and not to worry.

"I pushed him over into the recovery position and the others called the ambulance."

Mr Choruma was later pronounced dead at the scene.

Ms Jones told the jury that Adeyemi said in a prepared statement last December he “acted in self-defence” as he was “kidnapped by the victim and Hibberd.”

But she argued the force used was “not proportionate” for self-defence.

The trial continues.