Wendy Pearson, former head of PE at Dame Elizabeth technology college in Bournville, Birmingham, was advised that her claim was unlikely to be successful.
The National Association of Schoolmasters Union of Women Teachers, her union, also indicated it would not support her.
Miss Pearson, who has more than 25 years teaching experience, has already appeared before England's General Teaching Council and is awaiting its verdict.
She resigned as head of PE following a competency procedure and meeting of school governors, that found her unfit to teach. Her competency was questioned when inspectors in 1998 failed four out of five of her PE lessons.
At the GTCE hearing earlier this month Miss Pearson said she had been bullied and set up to appear incapable. The panel heard she had suffered stress and depression and suffered ill-health for most of 1999.