Continuity mistake: Tucker, Benny and Alan are chased out of Brookdale by five boys, but when they are in the street outside the school there are only four boys.
Character mistake: Miss Summers tells Mr Sutcliffe that she has to check on some our third year friends meaning Jackie Heron, Brenda and Lucy. But these three girls are in fact fifth years.
Visible crew/equipment: When Miss Mooney tells Roland he is exaggerating, a boom mike shadow is visible on the back of two girls' heads.
Visible crew/equipment: During the girls' PE lesson there is a boom mike shadow on the gymnasium wall.
Continuity mistake: During series 6 Jeremy Irvine (Jonah's cousin) is a pupil at Rodney Bennett school and a year younger than Jonah, but when Jeremy transfers to Grange Hill this series he is in the same year as Jonah.
Settling In - S5-E2
Visible crew/equipment: As Mrs Browning is leaving Mrs Mclusky's office a boom mike shadow is seen on the back of her coat.
Episode #4.4 - S4-E4
Continuity mistake: When Mr Hicks says "Move it, Stewart!" when Stewpot is climbing a vaulting box, Hicks is holding a basketball and his arm is stretched out, but when we see Hicks in the next shot, his arm is now by his side.
Continuity mistake: During the fire alarm when the staff and pupils are assembling in the playground, a boy points out judi trapped at a upstairs window to Mr Brisley by saying "sir look." There is no one behind them, the angle changes and there are now a crowd of pupils behind them.
Continuity mistake: During the memorial ceremony for Danny, Ronnie is reading a tribute but starts crying and is unable to finish it. Helen consoles Ronnie by embracing her, the angle changes to Ziggy and Robbie planting the tree and Ronnie and Helen have changed position - both are facing forwards, watching Robbie and Ziggy.
Plot hole: Becky finds the photocopies of Natasha's diary pages in Nick's locker. They all fall out onto the floor as she opens the door, she picks them all up and puts them back inside the locker. Later on at home Becky is reading the diary page about herself - where did she get it from, when she put all the copies back into Nick's locker?
Continuity mistake: While the end credits are rolling Mr McKenzie is taking a photo of Trev and Helen dancing. Behind them Gonch is dancing with Mandy. The angle changes and Gonch is now dancing with Calley.
Episode #8.1 - S8-E1
Continuity mistake: Trevor Cleaver gives Hollo his bag and tells him to put it on the seat furthest away from the teacher. In the first two shots Hollo is holding the bag the right way up, but in the third shot Hollo is holding the bag on its end.
Continuity mistake: At the start of the fight, a boy attacks Gripper with a chair. He is holding it upside down with the backrest against Gripper, who is holding the chair's legs and pushing the boy with it. The angle changes and the chair is the right way up, with Gripper pushing the other boy with it, holding onto the chair's legs. Another angle change and Gripper is holding the chair seat and pushing the boy with the backrest.
Episode #7.9 - S7-E9
Continuity mistake: When the argument starts between Glenroy and John Eastlake, Mr Fowler stands between them. Next shot Sue Shallcross is standing between Glenroy and Eastlake and separates them. Mr. Mcguffy then stands next to Sue, next shot Mr Fowler is standing between the two boys, then the angle changes and Sue and Mr Mcguffy are standing between Eastlake and Glenroy again, with Fowler standing next to Eastlake.
Continuity mistake: Claire Scott is leading the second section of the protest march, she sees the first section start marching towards the school, runs back and shouts "now." She is standing on the pavement in front of the marchers, as the march starts the angle changes and Claire is now in the road to the right of her previous position.
Plot hole: In this episode Mrs McLusky is horrified when Mr Sutcliffe suggests staging a girls versus boys contest and tells him that the school does not want to promote sexual inequality, but two episodes earlier (4-16) Mrs McLusky wouldn't let Trisha Yates choose technical drawing as an option, as it was classed as a boys' subject.
Visible crew/equipment: In the final scene in the headmaster's office when Mr Mitchell says "I know its your decision headmaster" the microphone is in shot at the top of the screen.
Plot hole: Doyle steals Alan's judo suit when he inadvertently leaves it in the corridor. Doyle tells Robo that he will leave it in the bike sheds overnight and will sell it to Junky Mead tomorrow. The next day Tucker arrives at school having bought the suit and says he saw it in Junky Mead's shop yesterday and bought it on his way in to school that morning.
Revealing mistake: When the drunk Andrew is asleep in the boys' toilet cubicle, the wall shakes when Tommy shuts the outside door when Alan and Justin leave.
Episode #4.1 - S4-E1
Continuity mistake: The fire alarm sounds and the school is evacuated, three shots are shown of pupils running down the same staircase - in every shot it is the same pupils descending the stairs three times.