A killer has been jailed for stabbing to death his teenage nephew after a petty argument over a mobile phone.

Alan Cooper knifed 14-year-old Jordan in front of the victim's grandmother - the killer's mother, Susan Smith. The three were living together at her home in Newriggs, Washington, Tyne and Wear, when 32-year-old Cooper struck.

After a five-day trial, a jury at Newcastle Crown Court convicted him of murder by a majority last week. He had admitted killing Jordan in February but claimed he had suffered an abnormality of mind which diminished his responsibility.

The jury heard Cooper had a history of violence towards family members when drunk.

Handing him a life sentence and ordering he serve at least 22 years before being considered for parole, Judge John Milford said Cooper was a "highly dangerous" man.

He added: "You have been a bully since you were a small child and given to losing your temper and using violence, which is more likely when you have taken drink. You took the decision to kill Jordan, which you did not repent. You take no responsibility for your actions."

The court heard that he and his nephew had bickered after the teenager used his uncle's phone to contact a girlfriend on Facebook. Cooper had teased Jordan that he would contact the girl later and an argument ensued.

Mrs Smith defused the row and her grandson watched television with her in her room. As they sat in the dark, her son burst in and attacked Jordan.

A statement on behalf of Jordan's family read: "This is not a victory for us. There are no winners out of this trial. It doesn't change anything. We have to live with our pain every day and the knowledge that we will never have Jordan back.

"The jury came to the right decision and we are grateful to them for that. Justice has been done and now we have to try to rebuild our lives without Jordan. We are a very close family and we hope that we will now be left alone to grieve in private."