He was called names and hurt by other children, and twice ended up in hospital after having been "accidentally" winded in the playground. In one incident he was pushed to the ground and kicked by five boys.
When his parents complained to the school, the other children involved were made to apologise but, says his mother: "It was done grudgingly and made matters far worse for our son."
In Year 5, Joel began to refuse food at home and cut out sweets, cakes and puddings. By the summer he had stopped eating almost entirely and could not swallow his own saliva. He stopped talking, or making eye contact.
After an acrimonious meeting with the head, in which bullying at the school was denied, his parents withdrew him from the school.
For the next two years, Joel battled with anorexia. He spent six months in hospital, three of them being tube-fed. Once, he ran into the middle of the road and lay down, saying he no longer wanted to live. He had a brief stint in a private school, which ended with him being re-admitted to hospital weighing less than 40 per cent of the norm for his age.
Joel made some progress in a hospital school and now, aged 12, has recovered from anorexia. He attends a secondary school for three hours per week and is tutored privately at home.
"Our son is a lot better," says his mother. "The school have been very supportive and are aware of the effects of bullying. Basically, it crushed him completely.
"I don't think schools can deal with it by calling in the parents. They need to work on strategies of anger management for the bullies. At root they are children who are very angry and they take it out on vulnerable children."