Mr Justice Brooke ordered Mr Patten to reconsider the case. Mr Patten had decided not to use his powers when he discovered that Bob Prior, a teacher at Claremont High School in west London, had been unlawfully dismissed.
The judgment reveals the problems grant-maintained schools may encounter in no longer having access to local authority lawyers. The judge said he did not understand how Mr Patten could reasonably have played down the seriousness of Mr Prior's complaint about the conduct of his dismissal hearing.
The judge told him to reconsider and criticised him for his delay in dealing with the complaint. He said a decision could have been taken in May 1992 but Mr Prior was not told the outcome until April 1993.
Mr Prior, head of technology, was alleged by the school to have faxed documents to newspapers which brought the school into disrepute, and to have failed to introduce new teaching methods in response to inspectors' criticisms.
The judge ruled that a committee which dismissed him did not have the legal authority to do so because it had not been appointed by the governors in accordance with the school's articles and instrument of governors.