Proposals to give anonymity to teachers accused of committing crimes against pupils such as assault would place a serious inhibition on the right to freedom of speech and could leave children at risk, the Society of Editors has warned.
The society's executive director, Bob Satchwell, raised the alert in a letter to all members of the House of Lords, which is considering the Education Bill.
Clause 13 of the Bill would, if enacted, give automatic anonymity to any teacher accused of committing an offence against a pupil, whether the accusation was made by the child or on his or her behalf.
"It will be a criminal offence for anyone - pupil, parent, police, school, local authority, whistle-blower, media - even to inform parents or public that an identified teacher has admitted that the allegation is true and has resigned, or been disciplined, or even cautioned for the offence," Mr Satchwell said in his letter.
"It would also be an offence to report that the identified teacher had been exonerated."
Lord Phillips and Lord Black had both raised these issues during the summer, and Lord Phillips was now proposing amendments to the Bill, which the society believed deserved support.
Mr Satchwell went on: "Lord Phillips believes the proposals would be a gross inhibition on freedom of speech: it would set a very dangerous precedent as people could be convicted for telling the truth."
The society appreciated teachers' fears about false accusations, but the most important issue was to protect children.
Mr Satchwell wrote: "Other media organisations share our concern that no one, including parents, could even discuss or raise the allegations publicly, without committing a criminal offence.
"To avoid prosecution, they would have to persuade a court to lift the reporting restrictions (even then, the court can only lift them in the 'interests of justice' with regard to the teacher's welfare, not on wider public interest grounds) or get the teacher's written consent, unless criminal charges are brought (or the Education Secretary/General Teaching Council for Wales publish information about disciplinary action which they have undertaken)."