A teenager told a tribunal he was locked in his former school's exclusion room after he stood up for a teacher who was allegedly the subject of racist taunts.

The boy was giving evidence in a case brought by a teacher who has made allegations against his former colleagues of racial discrimination, sexual harassment and bullying.

The boy told the tribunal: "I heard our teacher being called a black ***t by another teacher when I was waiting outside the classroom."

The witness claimed he was locked in a room with other students after arguing with the other teacher about the alleged racist comment.

Later the tribunal was told the teenager's teacher, who was bringing the case, met the boy in McDonald's and bought him a meal while supervising the witness statement he wrote.

The teenager said the teacher took the statement home and typed it on his computer.

He said: "The teachers were not fair to him. He did get abuse. I wanted to do the witness statement for my teacher not for a McDonald's meal."

The teacher, who was born in Nigeria, claims he has suffered distress and trauma and has not been able to get another job at a school since resigning last autumn.

He claimed in an employment tribunal yesterday that a teacher at the school said to him: "You look so trendy my mum would like to eat you up. She likes black men."

He also claimed fellow teachers made him cry in a staff meeting by calling him a paedophile and asking him why he had not stayed in his own country.

A list of complaints from parents of pupils and colleagues at the school regarding the teacher was shown to the tribunal.

One complaint alleged that the teacher had "broken wind in a pupil's face".

The tribunal was also told the teacher, who lives near Brighton, had made previous allegations of racial discrimination in one of his past jobs.

The case continues.