The protection would include those involved in court cases — until conviction — because of the low conviction rate for teachers accused by pupils.

The Conservatives are seeking to secure confidentiality for all school staff facing claims that they have harmed a child. David Willetts, the Shadow Education Secretary, said that an amendment to the Education and Inspections Bill was needed because of the dramatic rise in malicious and unfounded allegations that have wrecked teachers’ careers.

The NASUWT union recorded an increase from 41 allegations of physical and sexual assault in 1991 to 192 in 2004. Conviction rates fell from 12 per cent (five teachers) in 1991 to 3.6 per cent (seven teachers) in 2004.

The Tories hope that the amendment will be given a chance to be debated when the Bill returns to the Commons next Tuesday. But even though they took legal advice in framing their amendment, the Government looks set to reject it on legal and practical grounds.

Officials fear that it would trigger demands from other public sector employees, as well as proving difficult to enforce in close-knit school communities where details of serious claims are difficult to conceal.

At present, police are urged not to release the names of school staff unless they are charged. A spokesman for the Department for Education and Skills said: “There was recent guidance to the Association of Chief Police Officers making clear that anyone under investigation but not charged should not be named or details provided to the media.”

The National Union of Teachers urged the Government to try to use the Tory amendment to introduce extra legal protection. Steve Sinnott, the union’s general secretary, said: “The question the Government should be asking itself is whether there is a workable way of protecting teachers from mass publicity.”

Mr Willetts said: “I hope they do not object to this on fundamental grounds because it is what a lot of teachers are concerned about. This is something the teacher unions have been calling for and it is a growing problem.”

Chris Keates, general secretary of the NASUWT, said: “I think the level of accusations has gone up simply because children now are very aware of their rights but not their responsibilities. It has become one of the weapons in the armoury of children to make teachers’ lives difficult over some sort of perceived injustice.

“It has become common to have reported to me that children respond to teachers by saying, ‘I am going to make an allegation against you and you will lose your job’. An allegation is seen as proof of guilt and people’s family lives and jobs are affected by that.”

In one dramatic case this year, Charlie King, a senior technology teacher, said that his 30-year career was ruined by allegations from two teenage girls that led to a 13-month public ordeal. A jury took 30 minutes to clear him of indecent assault.

Mr King said: “Any hope of resuming my career has been dashed by the adverse publicity. After all I have been through, the prospect of going back into teaching is very worrying.”

Weeks earlier a judge said that the case against Lydia Gane, 63, was “weak and muddled” after she was cleared of assaulting a six-year-old pupil she had tried to restrain. The teacher, who had a 30-year unblemished record, said: “I don’t know if a younger teacher would have coped with this. It is incidents like this that stop people from entering the profession.”

In another dramatic case of false allegation, a music teacher who died in prison while serving an eight-year sentence for raping a pupil was posthumously cleared last month. The Court of Appeal quashed the conviction of Darryl Gee after a long campaign by his mother, Molly, 88.

The alleged victim made similar allegations against another man, John Hudson, who was jailed for 12 years. His conviction was quashed last year after a psychiatric expert concluded that his accuser’s recollection was “implausible”.

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