A HEROIC teacher reportedly restrained a teenage girl in an armlock as the stabbing of two other teachers and a pupil sent a Welsh school into a “code red” lockdown.

The girl was arrested on suspicion of attempted murder, and remained in custody in the early hours of Thursday, after the chaos erupted at the end of morning break at Ysgol Dyffryn Aman (Amman Valley School) on Wednesday.

One teacher was stabbed in the neck and airlifted out of school grounds, according to reports.

Another teacher was injured, and so was a pupil. Dyfed-Powys Police has said their injuries were not life-threatening.

Darrel Campbell – a teacher who is said to be the chairman of a local rugby club – reportedly entered the fray, disarmed the alleged attacker and put her in an armlock ahead of emergency services arriving.

He is said to not have been harmed during the incident.

Leader of Carmarthenshire County Council, Darren Price, said: “I would like to take this opportunity to praise the teachers, staff and pupils at Ysgol Dyffryn Aman for the way they have responded to this shocking incident.”

The school went into lockdown after a “code red” alarm sounded through the PA system, during which students and staff are said to have hidden in classrooms – with one pupil reportedly vaulting the school fence to get to safety.

The lockdown lasted around four hours between 11.20am and 3.20pm, resulting in a lengthy and anxious wait for parents who were seen tearfully hugging their children after they walked through the gates.

Footage of the incident has been circulating online, with a number of newspapers reporting the contents of one video in which a panicked pupil can be heard shouting about someone getting stabbed.

All three victims were taken to hospital with stab wounds but Dyfed-Powys Police said their injuries are not life-threatening.

The force also said a knife has been recovered.