Frustrated parents and guardians have complained that their children are reportedly queuing for the toilet for much of their half-an-hour lunch breaks, at the expense of getting to eat in time.
Others say their children have been embarrassed or reprimanded for needing to go during class time.
One parent said: “My daughter needed to go during class because she thought her period had started and didn’t want to explain that in front of 30 other children.
“She asked twice, politely, but was told no.
“Eventually she just said she was going. The teacher said she would be put in isolation if she walked out and she said that was fine, as long as she got to go.
"My son, meanwhile, says he was bursting and got told no twice, to the point he started crying.
"When a girl got up and put an arm around him, she got threatened with detention and he still wasn’t allowed to go.”
Parents have also flocked online to talk about the issue with dozens on Facebook community groups criticising the school.
One mum said: “[My son] also mentioned the toilet situation and was told they are teaching them to manage to hold and go at break but always massive queues.”
Another wrote: “My two are in Handsworth Grange. They’ve both said it's gotten worse since being back.
“I just don't get it, when you've gotta go, you've gotta go, especially being female too.”
Headteacher Nicholas Parker said: “Our students are able to use the toilets throughout the school day.
"Multiple toilet blocks are available before school, during social times and after school.
"We discourage the use of toilets during lessons due to the impact on lost learning but do allow our student access to them where necessary, and we are sensitive to and support the needs of our students, especially those with medical conditions.”