Alfred Scott stormed into Thamesview School in Gravesend, Kent, after his son complained he had been bullied by teacher Tom Neave.

Maidstone Crown Court was told Scott head butted the teacher then punched and bit him.

Mr Neave was teaching maths to pupils aged 11 and 12 years old when he took Scott's son out of the room for being disruptive.

He tried to bite me and he did bite my ear Tom Neave

The 31-year-old said his intention was to reprimand the boy and denied he was shaking uncontrollably and spitting while shouting.

The boy went home then returned with his father but when Mr Neave asked Scott to go outside the class he could not calm him down.

Mr Neave said: "Then he head butted me. I think my hands stayed by my side.

"I didn't try to take a swing at him. I tried to restrain him by holding his arms. I managed to get him to the floor.

'Prison inevitable'

"He tried to bite me and he did bite my ear."

Scott, 39, of Barset Road, Peckham, admitted he had gone to the school to "degrade" the teacher but he denied assault causing actual bodily harm.

He said: "It was my intention to treat him the way he treated my son - embarrass him, that's all."

Carl Hackman, prosecuting, said Scott had several previous convictions including wounding in 1983 and a caution for assault in 1997.

But Grahame James, defending, said Scott suffered from depression and had tried to commit suicide.

Granting bail and adjourning sentence until 5 September psychiatric reports, Judge Anthony Balston said prison was inevitable if there was not a hospital disposal.