The Pupil Referral Unit (PRU), known informally by pupils as the "sin bin", is a special unit at Waterloo Road to help pupils with their poor academic performance in the mainstream or with their disruptive behaviour. It was proposed by then Headteacher Michael Byrne and was funded by Lorraine Donnegan. Nikki Boston returned to Waterloo Road to head up the new unit in Series 8 Episode 11.
The entrance to the unit had two passcoded doors to maintain security and ensure only authorised access. The unit was under threat of closure on multiple occasions by Lorraine Donnegan due to budget constraints and her questioning its success. Students are moved back to mainstream once they have proven themselves.
- Phoenix Taylor was placed in the PRU from its opening day because of his poor Academic performance from the previous term. He left the PRU the following episode when he decided to leave school to work with his father. (Series 8 Episode 11 - Series 8 Episode 12)
- Rhiannon Salt was placed in the PRU from its opening day due to poor academic performance and disruptive behaviour from the previous term. (Series 8 Episode 11 - Series 8 Episode 22, Series 8 Episode 28)
- Jodi "Scout" Allen was placed in the PRU from its opening day due to her poor academic performance from previous term. Scout left the PRU at the end of spring term when she passed her A-Level English exam and went on to do teacher training at university. (Series 8 Episode 11 - Series 8 Episode 20)
- Barry Barry (Series 8 Episode 11 - Series 8 Episode 22, Series 8 Episode 28) was placed in the PRU alongside his sister Kacey due to poor behaviour in mainstream and a bad track record. He was previously expelled from previous schools and as such Waterloo Road's PRU was the last resort.
- Kacey Barry (Series 8 Episode 11 - Series 8 Episode 14, Series 8 Episode 18) was placed in the PRU alongside her brother Barry due to poor behaviour and after being expelled from her previous school.
- Jade Fleming (Series 8 Episode 13 - Series 8 Episode 20) was placed in the PRU for support with her academic performance.
- Connor Mulgrew (Series 8 Episode 16 - Series 8 Episode 17) was placed in the PRU following his admission that he had been the fire starter. He was placed in the PRU for close supervision.
- Lisa Brown (Series 9 Episode 5) was placed in the PRU because her maths ability wasn't up to scratch and it was believed she would have benefitted from the unit on a part time basis.
- Nikki Boston - Head of the PRU (2013-2014)
- Michael Byrne - Headteacher (2013)
- Lorraine Donnegan - Benefactoress (2013)
- Tom Clarkson - Deputy Headteacher/English Teacher (2013)
- Grantly Budgen - English Teacher (2013)
- Sian Diamond - Deputy Headteacher/Science Teacher (2013)
It is believed that teaching staff would be timetabled to teach students in the PRU away from mainstream.