Guest Stars Ncuti Gatwa as Eric Effiong Emma Mackey as Maeve Wiley Connor Swindells as Adam Groff Aimee Lou Wood as Aimee Gibbs Kedar Williams Stirling as Jackson Marchetti Alistair Petrie as Headmaster Michael Groff Mimi Keene as Ruby Matthews Chinenye Ezeudu as Viv Odusanya George Robinson as Isaac Goodwin Dua Saleh as Cal Bowman Sharon Duncan-Brewster as Roz Marchetti Conor Clarke McGrath as Courgette Connor Thaddea Graham as Sarah "O" Owen Reda Elazouar as Beau Alexandra James as Aisha Lisa McGrillis as Joanna Hannah Gadsby as Celia Anna Francolini as Gloria Masters Anthony Lexa as Abbi Montgomery Felix Mufti as Roman Bella Maclean as Jem Eshaan Akbar as Principal Lakhani Joe Hewetson as Student Jack Gleeson as Dodgy Mo Moyosola as Student Dolly Gadsdon as Darla Serranna Su-Ling Bliss as Young Sarah Claire Cogan as Caretaker Siobhan Gia Rose Patel as Young Ruby Hattie Morahan as Caroline Michael Lindall as Pierre Megha Dhingra as Student Samir Mahat as Student Keron Nicholas Day as New Student Isabella Picotto as Young Joanna Elly Roberts as Young Jean Elena Pitsiaeli as Student Naveed Khan as Delivery Man