The sister of murdered teen Peter Hagan has described her brother's four killers as "complete cowards" after they were jailed for 72 years yesterday.

Rodrica Hagan provided an emotional victim impact statement which was read out at the Old Bailey before the convicted quartet were sentenced by Judge Peter Rook.

Ms Hagan's words were directed at her brother's killers, all of whom are grown men in their 20s.

She said: "It is unimaginable how one night can change the lives of a whole family.

"We wanted those responsible to hear from us the absolute devastation they have caused.

"The pain is indescribable. The sense of loss does not seem to diminish and it is impossible to put into words.

"It is not a man who attacks anyone with a knife, it is a complete coward. Someone who cannot take someone on without a weapon.

"What happened to these young men to turn them into people who do something like this?

"But we forgive those who are responsible for Peter's death, we believe in God and we must forgive."

The Old Bailey heard how Peter's mother Yvonne Noah, who has fostered dozens of kids including Peter, is considering returning to her native Sierra Leone because of unbearable grief.

Ms Hagan added: "Our mother is a foster carer to over one hundred children but she feels she has failed Peter.

"The negative impact on our mother has been indescribable.

"We are worried about her health and she has not been at court to hear the details about Peter's death.

"She is considering moving back to Sierra Leone to try to cope with her grief.

"No remorse has been shown by the defendants which has made the experience even more distressing and upsetting.

"If there was any sight that upset us the most it was Malki Ferguson smiling in court as we grieved."

Peter, 16, from Brixton, was stabbed four times during the frenzied attack which took place at a birthday party in a flat in Albon House, Neville Gill Close, Wandsworth on February 17.

The party was being held to celebrate the 19th birthday of Jamilya Ferguson, sister to the Ferguson brothers, and she had invited the group of younger boys, including Mr Hagan.

About 25 people attended but the revelry was cut short once fighting broke after Jamaal Ferguson had apparently been insulted by one of the younger group.

A pathologist told the court Mr Hagan had died from a stab wound to the femural artery which caused significant blood loss.

Despite the efforts of paramedics who found him collapsed in a stairwell, Peter was pronounced dead at the scene.

Jamaal Ferguson, 23, of Albon House, Neville Gill Close, Wandsworth, was jailed for 21 years for Mr Hagan's murder.

Dean Harmes, 27, from Wentworth Court, Garratt Lane, Wandsworth, was handed a 17 year sentence.

Romell Martin, 22, from Fairgreen Road, Thornton Heath, was also jailed for 17 years.

A fourth defendant, Jamaal's brother Malki Ferguson, 22, was also jailed for 17 years.