Parents claim they are having to pay for a doctor's note to ensure their children are allowed to use the loo during lessons at school.
They say this was after their kids were told they could only go before or after school and during breaks or lunch.
The mums and dads at Marine Academy Plymouth have branded the new policy as "inhumane".
However, there is the exception to the secondary school's new rule of 'medical necessity'.
But parents are frustrated that they have to part with £22 for the doctor's note to enable their children to have a special 'toilet pass' from the school to allow this.
These pupils then still have to wait for permission from their teachers to use the loo during class time.
One mum, Carol Courage, says her daughter, 12, has been refused to use the bathroom on multiple occasions, even when she explains to the teacher she is desperate.
Courage claims her daughter has been punished with detentions for not following the rule, blaming what she believes is an "inhumane" policy on her daughter developing urinary tract infections (UTIs).
"It's a human right to go to the toilet," she says.
Two other parents, Shepard and Trevor Joyce, of another pupil at the same school, also 12, say their daughter doesn't even want to continue attending anymore.
In a similar situation, they also claim she suffers with UTIs and think the rule is just "horrendous".
"Our daughter has got to the stage where she doesn't want to go to school," they say.
"It's a nightmare because the biggest thing on her mind is not being able to use the toilets while she has the infection."
Marine Academy says the welfare and safety of its students "is always our first priority" and students are able to use the toilets "at the start of day, break time, between lesson transition, lunchtime and after school".
However, others have echoed similar frustrations at the rules on social media.
"How are they meant to concentrate on learning if they are needing the bathroom?," one user writes.
"Then girls having periods, could leak through underwear and then have to go home to wash and change – this actually happened a few times to my daughter. The rules in Marine Academy are getting worse."
"And I'm speaking as a parent who sent two children there," they add.
Another emphasises, "It is no one's business why someone needs the bathroom and even in the workplace, people are not usually restricted on bathroom breaks.
"It's a human right."
One "unhappy" parent whose son also attends the school says their child, who "said he would have an accident, if he didn't go straight away" was refused, and was given a detention for going anyway, while two other girls were allowed to go.
"A formal complaint has been made and have a call from school today - the policy is disgraceful and very unhappy parent," they add.
Another brought up health concerns. "Retaining your child from using the toilet can cause an infection - what a ridiculous rule."
"When I went to school all the money they asked for was your dinner money," they add, now happy to be an "old age pensioner".
However, others have compared the rules to what teachers have to put up with throughout the day. "Teachers have to wait till break times. How often does a teacher leave the class to go to the toilet?," one asks.
"Some of the pupils will become teachers in the future, so no harm getting them into the habit of going to the toilet at break times."
While these are the parents' opinions, what affect can a policy like this have on children's health and wellbeing from an expert's point of view?
"If children continually 'hold the urge' to pass urine, it can lead to overstretching of the bladder," says Dr Hana Patel. "Another complication is the development of urinary tract infections due to the back pressure of the urine, that then may cause kidney damage. However this is unlikely to cause long term problems if resolved quickly."
Dr Amit Sra (M.D, MuDr) of of Harley Street's luxury clinic Cosmebeauté acknowledges the purpose of bladder training in some instances before adding, "but in a school environment should a child need the loo it is advised they are allowed to minimise the impact on concentration of studies and emotional comfort".
"The need to urinate may be due to a urine infection and holding may further enhance the infection causing further distress," he says. "We are designed to void urine when our bodies require thus unnecessarily holding is not beneficial unless indicated."
NHS inform advice says that measures to prevent a UTI include "going to the toilet as soon as you need to pee and always emptying your bladder fully". NI Direct government services echo this, as not holding it in will help your unitary tract free from bacteria.
Its tips for preventing UTI's in children include "Encourage children to go to the toilet regularly and make sure they are well hydrated."
And it's not just the physical that can be affected by not being allowed to pee, but the psychological too.
“Each situation with a child is unique and policy needs to reflect this," says Psychotherapist Noel McDermott, with over 25 years’ experience in health, social care, and education.
McDermott acknowledges that the school needs to manage where children are, for example for their safety, but policies should have flexibility in exigent circumstances, and that certification that costs money is also unreasonable for parents struggling financially.
"Embarrassing children around bodily functions is never a good idea," he states.
"Creating anxiety shame and embarrassment around using the toilet is very poor practice," he says, before giving the example, "It’s possibly very distressing to young girls who are 12-years-old etc who may be starting their periods (12 is the average age for periods to start)."
This rings true to an incident described by one of the parents at the school.
McDermott adds, "As these kids are exactly this age it seems odd to me that the school would fail to have policies that are gender sensitive and create an environment in which young girls [for example] could face significant gender-based hate/bullying."
He also raises the point that bladder urgency itself can often be a sign of psychological distress in children. "To compound the distress with rigid and shaming rules is inappropriate and may indeed cause psychological harm."
Of course, the argument for the policy could be that not going to the toilet during lessons could help avoid lesson disruption, or incidents in toilets like fights or vandalism, or children skiving off during lunchtime.
Other schools might just make sure only one person goes to the toilet at a time during lessons, as this also helps to prevent friends going together and chatting, or avoiding class.
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Leigh Withers, Principal of Marine Academy Plymouth says in full, "As in all in schools, the welfare and safety of our students is always our first priority.
''Students can use the toilet at the start of day, break time, between lesson transition, lunchtime and after school.
"If there is a medical necessity to use the toilet at other times we discuss each case with parents to ensure the best support plan is in place and this may include a toilet pass. Also we do not have unisex toilets.
"We will be welcoming our largest ever cohort of Year 7s which is a testament to the excellent education and care students receive here at Marine Academy.
"As a school we have had to expand our allowed number of entries to fit the demand of parents who seek a school with high expectations, an academic focus and the clarity of vision which at its heart, states that every child who joins Marine Academy should have the opportunity to go to university when they leave.
"This year Marine Academy will see 80 per cent of its Year 13s moving on to University and the school will celebrate its greatest ever GCSE results that are likely to see it as one of the highest performing schools in the entire South West."
Additional reporting SWNS.