School children at Park Lane Academy in Halifax were held in the rain for around 45 minutes this morning in a row over green pens.
Several parents have contacted the Halifax Courier to express their disgust at the treatment of the children, many of whom rang for a lift having been told they would be sent home for not having the correct stationery.
They were reportedly told that they would need to bring green pens to school in order to mark the work of other children.
This morning, children's bags were searched as they were held in a rainy playground. Many children walked off site and parents arriving to collect their children rowed with staff.
One parent, who had arrived at school early for a meeting, described the scenes as 'chaos', claiming that the school had lost control of the situation.
She said: "It was ridiculous. There were dozens of children just stood out in the rain. It was cold and many of them didn't have coats with them.
"As I left the school there were kids standing at the bus stop, walking home, there were parents shouting at staff. They just had absolutely no control over what was going on. It was awful."
Shortly after 11am, parents received a message from the school's Principal Miss Lisa Corrigan, which said:
"Following the slow start to this morning's lessons we will be amending the morning procedures.
"As of tomorrow, different year groups will enter through different doors in order that uniform and equipment is checked more quickly.
"All students will be given a green pen today free of charge, but we ask that you maintain talking to your children about being organised for school."