Her lawyer argued that she acted in self-defence but after hearing from the witnesses none of the eight jurors agreed. The vote was five to three for attempted murder. The defence team plan to appeal the sentence.

The judge ruled that the 16-year-old must serve one year of her sentence in prison, and she has already spent three months of that in pre-trial detention. The remainder of her sentence can be conditional providing that she is on probation and continues with her education. She was also ordered to pay €1,000 compensation to her victim, who suffered serious injuries as a result of the stabbing.

This is the second time the case has come to trial. Initially the girl, then only 14, was charged with intentional aggravated assault. Based on the information available the judge ruled that she was not responsible – but the case was later handed over to be tried by jury.

The accused had started a new school shortly before the incident in May 2013, due to "disciplinary reasons", and she had problems with some of her new classmates, including the victim.

A month-long dispute involving insults, bullying and threats on social networking sites ended when the girl brought a knife to school with her. When one of the boys put her in a headlock she stabbed him. The prosecution said that her response was not self-defence as it was disproportionate and she had obviously meant to harm him as she had brought the knife to school after being threatened on Facebook.

The defence argued that the boy had kicked the girl in the stomach and then jumped on her chair and grabbed her in a headlock – and that she feared he was going to choke her to death.

The victim refused to testify before the judge but in police interviews he had admitted that he had written death threats to the girl but that he had never been serious.

Psychiatric experts testified that the 16-year-old girl had a "social behaviour disorder" and was unable to fit in at school.

She is currently living with her grandparents and continuing her education at home.