Teachers are facing an increased threat of being reported to disciplinary tribunals for misdemeanours committed outside school such as drink-driving and drug-taking.
A TES investigation has found that the number of outside-school offences being examined annually by the General Teaching Council for England (GTC) has soared from seven to 55 in the past four years.
The majority of incidents were about driving - largely drink-driving - with dishonesty, such as fraud, benefit fraud or theft a close second.
Teachers' unions agree that the GTC has a role to play in safeguarding the reputation of the profession. But some fear it could go too far in punishing teachers for offences unconnected to their careers.
Mick Brookes, general secretary of the National Association of Head Teachers, said: "If we ask our heads and teachers to be saints, we will have difficulty recruiting anybody. Clearly anyone found guilty of offences against children is unfit for teaching, but where do you draw the line with other offences?"
The GTC is today due to begin consultation on a new code of conduct, covering teachers' behaviour both in and outside school.
The body has been holding tribunals in Birmingham since 2002. Over the past four years, the hearings have examined 632 incidences of misconduct, nearly a fifth of which have occurred out of work.
Less common incidents have included possession of drugs and guns, as well as violent offences such as assault and even manslaughter. Some teachers have been punished for more than one offence.
The rise in outside-school cases is in line with overall referrals to the GTC, suggesting that the change is not an indication that teachers' behaviour is worsening.
The body has been urging local authorities and schools to follow procedure and contact the Department for Children, Schools and Families whenever they dismiss a teacher for misconduct, or if they believe a teacher has resigned before they could be sacked. Police are also meant to contact the department whenever a teacher is cautioned or convicted. Less than a third of teachers reported to the GTC last year faced formal hearings.
Chris Keates, general secretary of the NASUWT teachers' union, said the systems for deciding which cases should be heard had improved, but the union was still concerned by how teachers were investigated locally. "We have had people investigated who have had driving offences - not drink- driving - and we cannot see any link between that and people performing their job," she said.
David James, head of professional regulation at the GTC, said: "All cases, both at the investigating and hearing stages, are judged on their individual circumstances and according to a framework agreed by the council," he said. "We conduct all GTC hearings in a fair, unbiased and considered manner, and always in the public interest."
Double sentence, pages 20-23
Leading article, page 36.