On Wednesday 27 March 1963, after the last night's snowfall, Susan Foreman made a snowman with Gillian Roberts and John Brent, in the Coal Hill playground. Gillian hoisted up a Year One student named Sadie Lederer to let her make the face.
Later, when the afternoon register was called, Susan accidentally called her geography teacher "Ghastly" — the students' nickname for him — instead of Mr Grange. She was forced to write, "I will show respect at all times for the teachers of Coal Hill Secondary Modern School" 150 times. She instead started a diary to avoid this task, but eventually got around to it. She, however, lost count and ended up doing 153 lines. She figured she would probably get punished for the three extras the next day. (PROSE: Time and Relative)
Behind the scenes
While not stated in PROSE: The Clocks Go Forward, it is implicitly set in the week prior to 27 March 2005, given the upcoming shift to British Summertime.