Youngsters at Keswick School had to go into emergency lockdown after reports of an incident which could have put them in danger.
Initial rumours were that someone had a knife on the premises, but it is understood that a pupil caused alarm with their behaviour and was not armed.
Staff followed Government guidelines by initiating the lockdown procedure during the incident last Wednesday, October 11.
The school stayed in lockdown for seven minutes while staff confirmed that it was a false alarm.
A parent, who did not wish to be named, said pupils hid under tables, which is part of a typical lockdown drill, and staff barricaded doors to classrooms.
They claimed some pupils had texted their parents to ask for help.
Headteacher Simon Jackson said nobody was at any risk during the incident.
He added: “Some incorrect information was passed on and this resulted in a seven-minute lockdown following our school procedures.
“No-one had a knife. When the information was corrected, we lifted the lockdown immediately.”
Parents and carers were later sent a text message from the school. It read: “Our lockdown procedures were initiated this morning due to a false alarm, there was no danger to any students on site.
“We continued this as a lockdown drill. Please be reassured that all students are safe and are continuing with their lessons.
“The students followed procedures promptly and correctly.”
A further message to parents sent this week added that two police officers assisted staff during the incident.
It said: “There were two police officers in the school at the time for a completely unrelated reason.
“When the lockdown sounded, they did walk through the school but only in a capacity to help support the staff.
“The child was not arrested and left the school with their mum.”
