Now a strapping 15-year-old, with plans to make computer games, Paul can look back at his experience with a grin.
However, teaching staff at Oakdale comprehensive in Caerphilly are always on the look-out for the latest victim.
Pam Scourfield, deputy head, urged Paul to keep the diary but she believes every case is different. In one, a bully's dad was terminally ill, and he was taking it out on a fellow pupil.
The situation was resolved when the bully told of his despair and wrote to his victim's family saying sorry.
The school's anti-bullying policy urges victims to come forward, but it also offers salvation for the bully. Special assemblies have been held all this week. Karen Burns, head of support and guidance, believes there are always two sides.
Rows between friends can escalate into bullying complaints, only for the warring pupils to make up the next day. However, complaints are taken seriously, and "observers" placed on school buses and in the yard to check out bullies.
An anti-bullying post box is left out for victims unwilling to tell someone face to face.
The school prides itself on its low level of bullying - with not one report of in-school mobile phone or text bullying. Physical assaults are also rare.