Jonathan Dunning-Davies, 25, walked into Hull Crown Court in the last week of March with two alternative press statements at the top of his packed folder of documents. One expressed his relief that he had been vindicated of an allegation of indecent assault, described the past 12 months as a “living nightmare” and thanked his family and friends for their support.

The other announced that despite the verdict, he was not guilty and stated his intention to launch an immediate appeal.

In the event, after a two-day trial, the jury took 20 minutes to find Mr Dunning-Davies not guilty. He had been accused by a Year 10 student of grabbing her breast as 60 students made their way out of an IT suite - in the presence of three teachers - at Sydney Smith school in Hull, one Friday afternoon almost exactly a year ago. Mr Dunning-Davies - likeable, fresh-faced and still wearing the cartoon tie that used to amuse his students - was able to hand statement number one to local journalists. But both texts contained the sentence announcing that “I will never go back into teaching, becauseI we live in a ‘power to the pupil’ schooling environment. It is my opinion that - like packets of cigarettes and now bottles of alcohol - the career of teaching should bear a health warning.”

So Mr Dunning-Davies, a French graduate who comes from a long line of teachers, is lost to the profession. That he and his family have had an annus horribilis is not in doubt. In line with common practice, Mr Dunning-Davies was suspended - without pay, because he was working for a supply agency - soon after the allegation was made. Four hearings in front of magistrates and two appearances at the crown court, with delays resulting from bureaucratic muddle and lost prosecution documents, played themselves out over the course of the next 12 months.

Mr Dunning-Davies experienced the isolation and anguish universally described by victims of false allegations. Now working as a delivery driver for a firm of electrical retailers, he says he has had more support from colleagues there than he got from management at Sydney Smith school, the supply agency that found him the post, or Hull local education authority.

His primary teacher mother, Faith, and father Jeremy, a lecturer in physics at Hull University, have suffered perhaps even more than their son.

But Mr Dunning-Davies’s case springs from a context not only of what he termed “pupil power”, but of Hull’s acute teacher shortage. Although described in court as a teacher, and working as a teacher, Mr Dunning-Davies was not a teacher but a graduate who wanted to become a teacher. During a four-year degree course at Nottingham university, he spent time in a French school as a language assistant and enjoyed it. But when, after graduating in 2001, he applied for two PGCE courses, he was turned down because of his lack of experience in English schools. “They were also very critical of my private school background,” he says. “With hindsight, maybe they were right. I had no experience of discipline problems.”

One of Mr Dunning-Davies’s teacher-relatives alerted him to the graduate training programme, in which graduates are trained while working in schools. He applied to the newly re-organised Endeavour school in Hull and was taken on in the languages department to start in the autumn of 2001.

The interview, he says, was a formality. “It showed how desperate they were for teachers. Basically, they were prepared to take anybody and were offering the carrot of the GTP plus pound;15,000.”

Despite support from his head of department, the untrained ex-public school boy often found himself out of his depth, working with students from an area of Hull then known as “Little Beirut”. “It went from bad to worse,” he says. “There were days when I felt like crying and didn’t want to go back.

But I kept going because I thought the GTP was going to happen.” Students at the school told him he was their 25th languages teacher. “You won’t be staying long,” children said to him. “They never do.”

In March, after less than two terms, Mr Dunning-Davies was suspended from Endeavour after being accused by a pupil of tying him up with electrical cable. The rather more prosaic version - that he foolishly looped the cable of an overhead projector through a student’s rucksack straps, pulled the bag up in the chair where it sat and advised the owner that “he too could sit up” - was accepted by the Department for Education, which confirmed, after a wait of four months, that he could carry on teaching.

While waiting for the department’s decision, and shaken by what had happened, Mr Dunning-Davies resigned from Endeavour school. He tried a job in sales for the next few months. “I was rubbish at it,” he says. “And I really missed teaching.”

He discovered that the Select Education supply agency took on unqualified instructors and from September to December 2002 worked in almost all of Hull’s 15 secondary schools, teaching geography, music and woodwork, as well as his own subject. Just before Christmas, he did a day’s supply at Sydney Smith, a 1,400-student 11-16 comprehensive, and enquired after a vacancy for a Year 7 form tutor. He started on a temporary basis in January 2003 as an instructor (paid pound;95 a day), still hoping to get on to a PGCE course the following autumn.

At Sydney Smith, he taught his class maths, English, science, RE, geography and history. The year group was set by ability; his was set 11, out of 13.

Throughout this period, Mr Dunning-Davies’s teaching style, as he freely admits, was “a wing and a prayer”. With no formal training, he relied on memories of his own schooling and advice from friendly colleagues on the same corridor and teachers in the family. By half-term he felt he was “beginning to get there” with his class; he had begun a Year 7 rugby club at the school with an NQT friend, and was gaining some respect from students. Headteacher Derek Coe interviewed him and warned him for calling a pupil he had found listening at a door “Big ears”. But the head said he thought he would make a good teacher and indicated that he would take him on the GTP at Sydney Smith the following academic year. Mr Dunning-Davies was delighted and began to see his dream of becoming a teacher turning into reality.

That all came to an end in March 2003, when after providing cover for a Year 10 IT class - “I was still nervous because a lot of them were bigger than me” - the false accusation was made against him.

Jonathan Dunning-Davies, an untrained supply teacher with no union membership in Humberside, a region which post-Soham was jittery on child protection matters to say the least, was expendable. Deemed too inexperienced for training courses, he was used to stop gaps in Hull schools until the combustible combination of inexperienced “teacher” and vulnerable students went up in flames.