One parent said her daughter, who attends Castle View School in Canvey Island, Essex, was denied the use of a toilet during lesson time while on her period.
The parent added that her second daughter, enrolled at the same school, was also denied access, despite having an incurable autoimmune condition affecting her bowels.
The mother told The Times: “There are long queues to use the toilets at break times which means kids can’t get lunch and use the toilet in the same allocated time.”
Videos posted to social media captured chaotic scenes at the school, with children crowding in a field chanting: “Free our bladders because we matter”.
More footage shows students filing out of classrooms into halls, before gathering in corridors.
Steve Durkin, the school’s head teacher, told the newspaper: “Pupils are able to access all toilets before school, break times and after school. If a pupil requires access to the toilet during lesson time, they request a pass from their teacher and are allowed access.”
It comes after protests erupted at schools across Britain on Friday over strict new rules that stopped them from using the toilet during lesson time.
Secondary schools in Cornwall, Essex, Lincolnshire and Yorkshire were all reported to have seen angry pupils rioting against measures by shaking fences, flipping desks, kicking doors, or standing on playing fields.
One case in Richmond, North Yorkshire, saw police called in, although it is understood that no criminal action was taken by any force.
The reaction came after some schools installed locked gates in front of toilets during lesson time, although it is not clear why the action was undertaken simultaneously at apparently unconnected schools.
The mutiny was sparked by calls on social media, with Facebook being used to orchestrate action at Penrice Academy in St Austell, Cornwall.
A witness told Cornwall Live: “Just to let you know that my daughter has just called me to say the protest has got out of hand and students are flipping tables.”
Meanwhile, in Banbury, Oxfordshire, The Warriner School was forced to close after angry protests from parents and students over a ban on girls wearing skirts and a “gender neutral” PE kit that led to police being called.
A parent said: “The girls are getting the message that this is your fault because of how you dress; they are learning what it’s like to face blame over appearance.”
One pupil told the Banbury Guardian: “If teachers can strike over their principles, so can we.”
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