A 15-year-old schoolboy who stabbed a classmate in the stomach, leaving him fighting for his life, has been sent to a detention centre for a year.

The attacker, who cannot be identified for legal reasons, was said by his barrister to be suffering from Asperger syndrome, a form of autism.

At the time of the stabbing at the Suffolk state secondary he had been depressed, on Prozac and had not slept well for months. But the judge at Ipswich crown court said that he had a duty to balance the boy’s medical and psychological condition against the public’s disapproval of his actions and imposed the 12-month custodial sentence.

The boy admitted a charge of wounding. Mark Norman, defending, said the attacker came from a successful, decent and distinguished family.

“He is not wicked or stupid but highly intelligent but he suffers from an unfortunate combination of psychological and physical conditions.

The court heard there was history of ill-feeling between the two teenagers and that school staff were aware of their problems.

On the day of the attack last May the teenager had hidden a sharp kitchen knife down his trousers before he went into a maths lesson. When the victim left the class to take a phone call, the boy, who claimed he had been bullied, followed him into the toilets, grabbed him by the neck and pulled him on to the blade.

The injured boy suffered a severe knife wound and needed 10 litres of blood, double the amount the body holds, during life-saving operations at Ipswich hospital. He spent days in intensive care and suffered serious damage to his organs, including his liver and pancreas.

Although the teenager made a good recovery, he had to pull out of a football scheme and has been predicted C grades in his GCSEs which he will take this summer, instead of the expected As.

The convicted teenager was seen by staff fleeing the scene after the stabbing and when stopped had told a tutor: “I have really lost it, I have blown it now.”

In a statement to police he admitted lunging at the other boy but said he had not intended to kill him. He said it happened after a culmination of problems, partly because he claimed he had been verbally abused by the other boy and was worried about being beaten up.

“I was very tense - he had been giving me death stares,” he told detectives.

“I wanted to sort things out with him but he wouldn’t speak to me. I wanted to scare him and pulled out the knife I had with me for my own protection.”

Mr Norman said of the attacker: “He suffers from a chronic respiratory condition and after several mis-diagnoses he was found to be autistic.

“His behaviour was worsened by drink which he took to try to sleep, that lack of sleep, caffeine and Prozac he was taking for depression. It is tragic that his condition was not fully understood by everyone,” he said.