A teacher who was jailed for firing an air pistol near a group of youths has been told it would be "impossible" for her to get her job back.
Linda Walker was convicted of affray and possessing a firearm
Linda Walker, 48, was dismissed from her post at New Park High School in Eccles, Salford, in May 2005 after a disciplinary hearing.
She appealed against the sacking to the school's governors but lost in August.
The employment tribunal, being held in Manchester on Monday, has been brought by the NASUWT teachers' union.
Mrs Walker was convicted of affray and possessing a firearm in March 2005.
She said she fired the pellet gun near youths outside her home in Urmston, Manchester, after they terrorised her family.
Mrs Walker had been a teacher for 25 years and at the time was teaching children with behavioural problems aged 11 to 16.
She was jailed for six months but freed on appeal on 4 May 2005.
Almut Bever-Warren, current head of New Park High, said working at the school was stressful and challenging, and that teachers should remain role models and teach them how to function "without taking the law into their own hands."
She added: "I believe it would be untenable for Mrs Walker to advise pupils in anger management because undoubtedly pupils would question her ability to tell them what to do."
She said the school had many "unpredictable" pupils and she could not afford an "unpredictable member of staff".
"There are a number of reasons why it is impossible for me to employ Mrs Walker," she continued.
She said Mrs Walker's work had never before fallen below expectation.
But she added: "The problem, I thought, was whilst I accept there had been no indication of Mrs Walker not fulfilling her role to a satisfactory standard, that one slip was one too many.
"The young people you are dealing with at New Park are the same type of young people she felt harassed by."
Mrs Walker is expected to give evidence on Tuesday.
The hearing is expected to last four days.