A man who gave a teenager a fatal dose of methadone has been jailed for ten years.

James Whitson gave the heroin substitute to Vikki McGovern knowing she wanted to kill herself.

Within two days the 19-year-old had died after taking the methadone at a hostel in Edinburgh's St John's Hill.

At the High Court in Edinburgh on Wednesday, Whitson was sentenced to ten years in prison.

Judge Lord Pentland told him: "Your conduct involved a great degree of recklessness and irresponsibility and this must be reflected in the sentence of the court.

"She was a highly vulnerable and disturbed young woman with pronounced suicidal tendencies, a number of mental health difficulties and a propensity for self-harming."

It is the second time he has been convicted of the culpable homicide of Ms McGovern. In 2009 he was jailed for ten years but the sentence was overturned on appeal after lawyers argued the jury had been improperly directed in the first trial.

Whitson was convicted for the second time in November after a five day trial at the High Court in Dundee.

There Pamela Bowmaker told the court how her daughter "changed" after the death of a close family friend.

She said: "She didn't really react to the death - she went in to herself instead. She went really quiet and that's when her problems started. She was normally a bubbly, outgoing girl before that. Vikki was just a happy-go-lucky person.

"But after that she started self-harming - cutting herself on her arms. She moved into a flat where she had support if she needed it. Then she moved to St John's Hostel and took time off college with a view to going back later."

Miss Bowmaker said just months after that move in June 2008 her daughter had tried to kill herself.

She said: "In August 2008 she sent me a text message saying she was sorry and that somebody had given her methadone and that she was in hospital. She said she loved me and her brothers and sisters and that she would never do it again. I visted her at her hostel and she said that at the time she had wanted to die.

"After that I saw her every day. On September 20 the CID came to my house and told me she had died."

The court heard that Ms McGovern tried to kill herself 13 times in the three years before her death. When she was found on September 20 2008 she had a lethal dose of methadone in her system.

Medical experts told the trial that those had been taken on top of a cocktail of other drugs including diazepam.

Witnesses told the court that Whitson had given Ms McGovern methadone just a day or two before she died.

Prosecutors alleged that he was fully aware that she had tried to kill herself using methadone previously, and was likely to do so again.

But Whitson, giving evidence in his own defence, claimed he had given Ms McGovern a watered down mixture of just 20 millilitres of methadone mixed with 80 millilitres of water. He said that he didn't think that amount of the drug would be dangerous to the teenager.

Whitson's lawyers had also lodged papers claiming two other people may have been responsible for supplying Vikki with the methadone that killed her.

Whitson, 33, a prisoner at HMP Edinburgh, denied a charge of the culpable homicide of Vikki McGovern by culpably and recklessly supplying her with methadone on September 18 in the knowledge she was likely to use it to commit suicide.

He admitted a charge of supplying Vikki and another person, Stuart Hedges, with methadone between November 12 2007 and September 18 2008 at two addresses in Edinburgh.