Pupils who make malicious allegations against teachers should face criminal charges, a union said on Monday.

The NASUWT said false claims remain "an enduring problem", blighting the lives and careers of accused teachers.

It called for urgent action to make sure that those responsible face punishment.

The union published figures showing that 103 of its members faced criminal allegations last year.

Of these, only four resulted in court action, 39 cases are yet to be concluded and the rest (60 in total) were not taken forward.

The figures were published as the NASUWT passed a resolution at its annual conference in Birmingham which said it believes "the most effective way to protect teachers from malicious allegations is to make such an allegation a criminal offence".

It called on the union's executive to "take action to bring about the necessary legislative change".

Phil Dunn, a physics teacher from Walsall, told delegates: "Malicious allegations eat away at the very fabric of our professional standards.

"The NASUWT has successfully highlighted the blight on the accused teachers' lives and their families, with often lengthy suspensions. Many teachers are simply unwilling to return to teaching following such allegations.

"Strong clear legislation would make the consequences of such allegations plain and clear to pupils and families.

"I will not defend any teacher who has betrayed the basic tenets of our profession. Child protection remains one of the basic foundations of our profession.

"But, colleagues, malicious allegations threaten to undermine that very basis."

NASUWT general secretary Chris Keates said: "These figures demonstrate that the issue of false, malicious and unsubstantiated allegations against teachers continues to be an enduring problem.

"Teachers' fear of having allegations made against them is very real, yet four out of five did not feel that current protections for teachers are adequate.

"The coalition Government has made bold promises of handing power back to teachers, but the new powers to search and restrain pupils, which teachers did not want, will leave them even more vulnerable to allegations and litigation.

"The fear of having an allegation made against them is compounded by the fact that, even if they are exonerated, their career will be permanently blighted by the fact that the allegation will remain on record.

"Urgent action is needed to bring in statutory provisions to cover the recording and reporting of allegations on a teacher's file."

According to research commissioned by the Department for Education, nearly half of allegations made against teachers are malicious, unsubstantiated or unfounded.

The survey, which examined the number and nature of allegations of abuse referred to 116 English councils between April 1 2009 and March 31 2010 found that of 12,086 allegations referred, 2,827 (23%) were against school teachers while a further 1,709 allegations of abuse were made against non-teaching staff in schools.

Almost half (47%) of all allegations made against teachers, and two-fifths (41%) of those made against non-teaching staff members were found to be unsubstantiated, malicious or unfounded.

But 18% of school teachers and 29% of non-teaching staff were suspended while accusations were investigated.

And one in eight teachers (12%) and nearly a fifth of those non-teaching members of staff (19%) faced a criminal investigation.

Just 3% of concluded investigations against teachers resulted in a criminal caution or conviction; for non-teaching staff this figure was 5%, the survey found.

This is based on information held by councils rather than the police.

A DfE spokesman said: "Schools should have absolutely no tolerance of malicious allegations against teachers. We've made crystal clear that heads can suspend or expel pupils who make false claims - and should report them to the police if they believe a criminal offence has been committed.

"All investigations must be quick and thorough, with unfounded allegations stripped out of individual teachers' personnel records.

"We've legislated so teachers have a legal right to anonymity before they are charged with an offence, to prevent their names being dragged through the mud."