A pupil told the Examiner last night: “I got a detention today for not having my calculator, even though I didn’t have maths today.

“My calculator was not at home, it was in my maths classroom because that is where I keep it.

“Even though I told my teacher that I did have it in another classroom, she still gave out an after-school detention.”

At 10am yesterday head teacher Carol Gormley told pupils in assembly that at least 200 children had been given a one-hour detention after school.

The number is believed to have risen during the day and may have got as high as 500 – one in three pupils at the Linthwaite school.

Mrs Gormley told the Examiner last night: “During the last term we experienced a huge increase in the number of students routinely arriving at school without the basic items of equipment we expect them to have each day.

“It is extremely disruptive to learning when large volumes of students need to borrow equipment from their teacher or our Student Services bureau.

“We educate our students to be responsible for their own organisation and it is unacceptable to arrive at school without basic equipment.

“Before the Easter holidays I wrote to every parent and carer stating our concern at the scale of the problem caused by this persistent lack of equipment. I stated that the sanction after the holidays for failing to bring a full set of basic equipment would be an automatic after school detention.

“Our aim was to allow parents the two-week holiday period in which to ensure their child had all the required equipment.

“A text message was sent on Wednesday last week as a reminder of the expected list of equipment and of the sanction for failure to bring the equipment from the start of this term.

“A check was carried out this morning and students without all their basic equipment have been issued with the after-school detention.

“We hope that parents understand that the cumulative effect of large numbers of students arriving routinely at lessons without basic equipment has a detrimental effect on learning and that they will support us while we address this issue.

“It can be difficult for parents to appreciate how much this particular problem can get in the way of teaching in such a large school. We expect the prospect of a detention to act as an incentive to students to take responsibility for bringing all their equipment in future”.