Every male teacher lives with this fear. But when Chris, a 41-year-old drama teacher, was called to the head's office one Wednesday morning in February last year, it was the last thing on his mind.

He was met at the door by his union representative, who told him he had been the subject of a serious complaint. A parent had written a letter claiming that Chris had indecently assaulted her daughter.

Chris was about to become a casualty of a disturbing syndrome which teachers' unions say is reaching epidemic proportions. They believe children, empowered by a greater awareness of abuse, are ruining lives by making misguided or even malicious allegations. Next week the unions, along with local education authorities, will publish a new code of practice designed to ease the plight of such teachers.

Last year police completed 139 investigations into child abuse claims against members of Chris's union, NASUWT, the second biggest teachers' union. In 130 cases - including Chris's - they failed to find enough evidence to bring a prosecution. The number of new allegations more than doubled between 1991 and 1993, from 71 to 158, and other unions say they have experienced similar increases.

But to be innocent in the eyes of the law is often not enough for a teacher. Even an element of suspicion can lead to a wrecked career.

Chris left the meeting with his headteacher feeling distraught but believing that his innocence would soon be proved and his reputation, built up over 19 blameless years in the profession, restored. Instead he has been projected into a Kafkaesque world in which he has been found innocent yet cannot clear his name. A mild, quietly spoken man, he says his biggest mistake was to befriend his pupils. He trusts few people now, least of all the children to whom he once devoted his life.

The girls who accused Chris were a trio of friends, all aged 10. Their year-group had been attached to his large, middle-class city comprehensive school because of a reorganisation. Chris says he had a good relationship with them but they tended to be fussy, chasing him up if he was a minute late.

On the day in question, the girls came eager to perform a 'circus play' they had written the previous week, although an improvisation class had been scheduled. The class was in a dining room with ceiling-to-floor windows. Chris spent the time helping the little groups of pupils, then sat down with the rest of the class to watch the circus play. It was not a success; the other children became restless and Chris wound it up.

The girls went to get changed, taking a pass-card from Chris to show that they were allowed out of class. They returned before the lesson ended and stayed behind afterwards to tell Chris how sorry they were that their act had been a failure, then they visited him in the staff room to return the pass-card. None of them seemed distressed.

The allegations emerged the following day, when the children's parents complained to the head. One girl said Chris had touched her chest and stomach as she rehearsed her act; another that he had run his hand up her leg as she stood on a stool during the performance. The third girl said she had seen everything, though her statement varied from the others.

None of the other 24 children in the class had seen anything, despite the fact that the second incident was supposed to have taken place while the whole group was sitting in a circle watching the girls.

Chris phoned in sick the day after the accusation was made, unable to face teaching. Two days later he learnt that the girls' parents had called the police, and he was suspended. His solicitor told the police that he was ready to be interviewed.

For more than a month nothing happened. Chris carried on rehearsing for a show in which he was due to appear and tried to live as normal a life as possible despite being unable to eat or sleep properly. Eventually he was called for interview by local authority officials, and came away feeling much better for having given his side of the story.

But four days later, at 7.30am, there was a furious banging on his front door. His visitors were three plain-clothes policemen and they told him he was under arrest. They handcuffed him and took him out of the house, leaving his elderly father standing on the stairs.

The police interview went on for 13 hours. Why would these girls lie? Why was he not married? Had he been close to his mother? Could he explain the difference between the male and the female mannequins he kept in the school wardrobe?

Meanwhile, the police went back to Chris's house and removed a box of videos, which they proceeded to watch. They were all of amateur dramatic productions in which he had appeared, including Lionel Bart's Oliver] and Willy Russell's One for the Road. They also took a mirror bearing a line drawing of the Copenhagen mermaid.

At 9pm, exhausted and dejected, Chris was told that he was to be charged with indecent assault and was put in a cell for the night. He asked repeatedly for water but ended up drinking out of the toilet because none was brought. He spent the night imagining all the things that could happen to him in prison: isolation under Rule 46, beatings, even castration. The next morning he was taken to court, formally charged and, to his relief, given bail.

During the next two months, Chris seriously contemplated suicide. He borrowed a piece of hosepipe and worked out how he could connect it to the exhaust of his car. Friends realised what he was planning and stopped him.

Then events took a turn for the better. When he returned to court to have his bail renewed, the charges were dropped. There was insufficient evidence to proceed with a prosecution.

'I thought that was it. I was told they had got to give me my job back now,' he says.

But the school governors and local authority had other ideas. Chris had been sacked a few days before the charges were dropped, and they had no intention of reinstating him. Nor was there any obligation for them to do so. Employers can dismiss an employee if they believe, on the balance of probabilities, that an incident has taken place. The mere existence of an allegation was enough to tip that balance against Chris.

Appeals to the local authority and an industrial tribunal failed to win his job back. Now he can only apply for for menial jobs, and has little hope of rebuilding his career. He is unable to think of a reason why the girls should have chosen to make up such a story.

'The implications of this will go on for the rest of my life. I am washed up and ruined. I am outraged and bitter and upset at my treatment. I am innocent and there are people out there believing I am guilty,' he says.

The Children Act and the change in attitudes that led up to it has given children the right to be heard when they allege abuse by those in authority. The vast majority of teachers accept this is a good thing but all the teachers' unions as well as the Council of Local Education Authorities (CLEA) agree that something now has to be done to protect teachers. They feel that things have gone too far.

Their code of practice will call for a review of police and Crown Prosecution Service practices to eliminate heavy-handed tactics and long delays. It will also call for a preliminary investigation before any teacher is suspended, and will demand that all cases are brought to a conclusion rather than ending, as Chris's did, with a cloud hanging over the accused person.

Although he would love to return to teaching, Chris cannot see how he could face a class of children again. He says society has whipped itself into a state of hysteria about abuse in which it has become impossible to believe that a child would ever lie.

Chris trusts few people now, least of all the children he once devoted his life to. 'If I saw a child fall over and start bleeding, I would walk by on the other side of the road,' he says. 'I would not go anywhere near, although my instinct would tell me to pick it up. The only way I could be safe now would be to join a monastic order and close the walls around me.'

(Photograph omitted)