A TEENAGER who slashed his former girlfriend's back with a craft knife as they had sex has been spared jail.

James Mildenhall was high on drink and drugs when he pulled the blade on the 17-year-old and also tried to throttle her with his hands.

But after hearing it was an unusual case and that the victim now wanted her 18-year-old ex to get help rather than punishment he was put on a suspended sentence.

A judge at Swindon Crown Court heard the incident was completely out of character for the student, who should not have been drinking after taking anti-depressants.

Hannah Squire, prosecuting, saida few weeks after splitting from a short relationship the couple, who had known each other since they were 11, met up at a friend's house.

After drinking lager and vodka together, and Mildenhall also smoked cannabis, they were left alone for a while.

As they were having consensual sex the girl felt three 'thuds' to her back before the defendant grabbed her round the throat.

After struggling free she found she had been slashed to the back with the blade as Mildenhall said: "It is not normal. It is not normal to try and kill someone. I need help."

When she was taken to hospital she was found to have three cuts to her back, though none were particularly deep and were glued back together.

Mildenhall, of Wills Avenue, admitted unlawful wounding.

Mike Pulsford, defending, said the month after the incident his client sat his A-levels and he is now at the end of his first term on a business management degree in London.

Before his first appearance in front of magistrates he said the victim sent his client a Facebook message wishing him luck in court.

Mr Pulsford said: "He can't explain why he did it," adding that he was very sorry for what he had done.

He said he suffers from dysthymia and was smoking about £20 of cannabis every other day at the time of the offence.

Since then he said he had stopped his use of illegal drugs and had greatly cut back on his drinking.

The court heard that teachers at his school were amazed to hear what happened saying he had shown no signs of violence describing him as 'just quietly sad'.

Passing sentence Judge Tim Mousley QC said: "You told the police that when you did what you did to her you felt out of it.

"You said at that point you found walking difficult as to what you had consumed. Later that night you vomited repeatedly.

"When you inflicted the wounds you weren't feeling anything: it is what you called an automated reaction.

"You have not hurt anyone before, not thought of hurting or scaring her before. When you sobered up later that night you had become extremely remorseful."

He imposed 16-month jail term suspended for 18 months with 25 days of rehabilitation activity requirement and 150 hours of unpaid work.

He also made a mental health treatment requirement to ensure he gets help for his problems.