A science teacher has been arrested on suspicion of attempted murder after a boy of 14 and two other pupils were hurt at a Nottinghamshire school.
Pupil Jack Waterhouse is said to be in a serious condition in hospital following the incident at All Saints' Roman Catholic School in Mansfield.
Science teacher Peter Harvey, 49, is being held in police custody.
Detectives have been granted extra time, until 2015 BST on Friday, in which to question him.
Det Supt Adrian Pearson said a weapon was used and there were a "number of witnesses".
Police said the incident took place at the school in Broomhill Lane on Wednesday.
Jack was taken to King's Mill Hospital but transferred to Queen's Medical Centre (QMC) in Nottingham where his condition is described as very serious.
Nottinghamshire County Council, the local education authority, said Jack's condition "slightly improved" overnight.
Police said the two other children who were assaulted were well enough to return home on Wednesday evening.
The school has declined to comment "at this time".
All Saints' School opened in 1974 and has 1,170 pupils on the roll, including a sixth form of 200 along with a teaching staff of more than 70.
The school, a specialist performing arts college since 2002, describes itself on its website as, "a lively, Catholic comprehensive school with a very special, warm ethos which is recognised by all who visit".
At a news conference Mr Pearson said: "Obviously the whole class is traumatised by what has happened.
"People send their children here from great distances because of its academic record and what happened is very much out of character for the school.
"I know a number of parents have rung the headteacher about what has happened but I would appeal for everyone to be calm, particularly in relation to those people involved."
In a statement Nottinghamshire County Council said: "An incident involving a pupil at All Saints' School occurred.
"The student was injured and has been taken to hospital where he is receiving treatment. The parents of the pupil involved have been informed.
"The matter is currently being investigated and it would be inappropriate to make any further comment while the investigation is ongoing."
I know there's no excuse for hitting the boy with something. Let's see what comes out of this, my money is on the boy winding up the teacher, pushed over the top. In a way, I feel sorry for the teacher already and I'm sorry if the boy was innocent but I doubt it.
Another balls up by H&S and all the do-gooders out there. Bring back the rights for teachers to punish pupils who step out of line, it never done no-one any harm in the past.
I know there's no excuse for hitting the boy with something. Let's see what comes out of this, my money is on the boy winding up the teacher, pushed over the top. In a way, I feel sorry for the teacher already and I'm sorry if the boy was innocent but I doubt it.
Another balls up by H&S and all the do-gooders out there. Bring back the rights for teachers to punish pupils who step out of line, it never done no-one any harm in the past.
'Paramedics found the teenager unconscious in a pool of blood at the entrance to a classroom in the school's science block.
He is in a stable condition at the Queen's Medical Centre in Nottingham, where he is being treated for a bleed on the brain and a fractured skull.
Former pupils arrived at the court with letters of support and good luck cards for physics teacher Mr Harvey.
One girl, who did not wish to be named, broke down in tears outside the courtroom after seeing her former teacher in the dock.
Another ex-pupil, Joseph Smith, 18, said: "I just wanted to come here today to show support. He was my form tutor and he was a good teacher. It was upsetting to see him in there. I got a bit emotional." '
Sounds to me like he was pushed over the top. I hope the other pupils aren't afraid to tell the truth about what happened, not just on that day but a build up to events.
The pupil was hit with something to the head. The teacher hadn't long returned to work after an illness.
Neighbors of the boy say he was a nice quiet boy, well kids are, when their close to home. We were all kids once and we all lead double lives, fooling our mum's that we were perfect. Well I did and so did all my mates too!
I hope the boy makes a good recovery for the teachers sake.
Neighbors of the boy say he was a nice quiet boy, well kids are, when their close to home. We were all kids once and we all lead double lives, fooling our mum's that we were perfect. Well I did and so did all my mates too!
I couln't have put it better my self if I tried bud
Uncertainty or not knowing causes depression, Im happy because I know I'm going to die one day!