A teenage schoolgirl has been locked up over an acid attack on a fellow pupil.

Emily Bowen poured One Shot drain cleaner into a viola case owned by Molly Young after she found out the girl was dating her former boyfriend.

Ms Young was severely injured when she pulled her viola case from a shelf and the liquid poured over her legs.

The victim was left "screaming in pain" as the acidic drain cleaner burned her skin during the incident in a music room at Knox Academy in Haddington, East Lothian.

Bowen, now 18, previously admitted to recklessly and culpably pouring sulphuric acid into a viola case in the knowledge it would be removed from a shelf by the victim, causing sulphuric acid to spill onto her legs, on September 29 last year.

She appeared at Edinburgh Sheriff Court on Monday for sentencing where a sheriff described the acid attack as "utterly wicked".

Sheriff Michael O'Grady QC said: "In the period leading up to these events you actually researched this topic and you of all people should have been aware of the potentially horrendous consequences for any young woman maimed by this mechanism.

"You have left a young woman to suffer a terrifying ordeal and she will be both physically and mentally scarred for the rest of her life."

Sheriff O'Grady said he had no option but to send the 18-year-old to a young offenders institution for 21 months.

He also banned Bowen from contacting her victim after sentencing her to a five-year non-harassment order.

Previously the court was told both girls were acquaintances and were members of the East Lothian school's orchestra before the incident.

Bowen played the clarinet while victim Molly played the viola.

The "talented musicians" fell out when the victim began going out with an ex-partner of the teenage attacker.

Prosecutor Aidan Higgins said both pupils were in sixth year at the time of the offence.

Mr Higgins added police found evidence on Bowen's phone of her researching acid attacks and how long the attackers were being jailed for.

The fiscal said: "The accused entered the music room and took down the girl's viola case, opened it and poured a quantity of drain cleaner over the viola and inside the case. She then placed it back on the shelf.

"When the victim went into the strings room she was aware of an eggy smell. She then took down her case and she was immediately aware of red liquid spilling from the bottom of the case and landing on her right leg.

"She looked down and saw her tights were disintegrating and she was aware of an intense burning on her leg."

Bowen was then identified as the culprit because a boy had spotted her crouching down inside the deserted music room ten minutes before the incident occurred.

The victim, now 18, was subsequently taken to Edinburgh Royal Infirmary for treatment to her injuries and eventually was transferred to St John's hospital for plastic surgery treatment.

Defence solicitor Jim Stephenson told the court Bowen had recently been diagnosed with autism and was suffering from depression.

Mr Stephenson added his client "struggles to deal with things" and she has a "supportive family" but asked for a community order to be imposed so she can be monitored.

Sheriff O'Grady told the acid attacker: "You should understand there is currently a very real public concern and fear about the emergence of this awful substance.

"It must be plain to anyone who resorts to acid for whatever purpose that the courts will not tolerate its possession or use for any criminal act.

"It is with considerable regret that I have come to the conclusion that nothing but a custodial sentence is appropriate."

A spokeswoman for East Lothian Council said: "The police were promptly notified and this was an isolated incident.

"We wish to reassure the school community that the council takes any incidents of violence extremely seriously, and in this case, all correct protocols were followed."