Despina Pavlou, who was dismissed from Lord Grey School last November for bullying and harassing staff, has won the right to claim she was unfairly sacked on grounds of disability.

Earlier this year a pre-trial review heard Ms Pavlou was suffering a 'mental impairment' in August last year – four months after she was suspended from her post – when she was assessed by a consultant psychiatrist and psychologist.

In her report psychiatrist Dr Elham Aldouri said the ex-head had a 'moderate depressive episode' which affected her 'memory and the ability to concentrate on tasks'.

George Plenderleath, the chairman of the hearing, said Ms Pavlou was suffering from a disability within the meaning of the Disability Discrimination Act 1995.

He added: "I find on the balance of probabilities that the claimant's depression started no later than August 2006.

"It had a substantial effect upon her ability to concentrate on tasks and if it were not for the measures being taken to treat her condition it was likely her depression would continue for 12 months."

Ms Pavlou, who had been headteacher at Lord Grey for six years, was relieved of her duties in February last year after she was arrested on suspicion of assaulting one of her deputies.

However, no charges were brought, but she was formally suspended the following month while an internal investigation was carried out.

Last November, Ms Pavlou was sacked and lost her eventual appeal. The tribunal, expected to last 10 days, will take place in Bedford later this year.