Kelly Marsh, from Buckshaw Village, says her 16-year-old daughter Bethany fell foul of school rules after completing one of her GCSE exams.
She found the nearest toilets were locked and says teachers declined to unlock the facility.
The school says only some toilets are locked at certain times of the day.
Here is a selection of what Post readers make of it.
Louise Holden: “It's the same at my children's school in Penwortham. It's so wrong. Penalise everyone because of a few idiots.”
Colin Thornborrow: “Imagine if this happened in a workplace. Why is this acceptable in a school? Would the staff adhere to the same rules?”
Vicki Niki: “Seriously?! And at an age where discreet toilet breaks are needed? Shame on you school.”
Donna Jones: “Bowel conditions likely to have a special pass. Staff cannot leave classrooms except at break and lunchtime. Trying to avoid gathering, bullying etc in toilet areas.”
Emma Walker: “Most schools do this. Children that have a medical need have a pass for the toilet it's been done in high schools at least the last 6 years.”
Annie Rodgers Livesey: “It’s so so wrong, my daughter has a toilet pass due to medical issues and she can't use it as all toilets are locked. When she went to the office they said they don't have the keys. I understand that all schools have an issue with vaping but to punish the ones that genuinely need the loo is wrong on so many levels.”
Tracy Mccormick: “They need to get a grip these kids need to use toilets what ever next eating dinner while they are working.”
Kate Roberts: “Basic violation of human rights.”
Tracey Mawson Lockie: “What if a child has IBS, Crohn's or if a girl is experiencing a heavy period? These children need to have full access to the toilets, no matter what time of day it is.”
Helen Newbury: “There’s got to be a balance between children running riots in the toilets and those using the facilities.”
Natalie Battye: “Sorry but this has caused many girls problems that have ended up quite embarrassing for a girl it should not be allowed.”
Louise Butterworth: “It’s the same at my daughters school in Penwortham. Blocks locked off.”
Alison Taylor: “I think it’s absurd disgusting, denying children of opportunity to use the toilet, for gods sake, what’s it going to be next; locking the loo at work because you don’t get paid to pee. This stupid, disgraceful rule warrants parents protesting over.”
Tracy McEwan: “Ridiculous, can't go running round looking for a toilet when you’re desperate.”
Mj Ebdell: "To encourage them to be in lessons rather than in the toilet"? When I went to school we had no choice, if we didn't go to lessons we had detention and stayed even longer. And in high school if we wanted to leave the class to go to the toilet we were told we were old enough to be able to hold on for an hour and had to wait.”