A school pupil has been reprimanded by police for making a false allegation of assault against a teacher.
Teachers union the NASUWT said the member was suspended after an allegation in 2006, but Flintshire Council and police proved the claim to be "malicious".
The teacher has now been reinstated at the school, the union said.
The NASUWT added it was a "huge step" towards showing students false claims against teachers were "unacceptable".
Suzanne Nantcurtis, NASUWT's national executive member for north Wales, supported the teacher involved.
She said: "The consequence of investigations was that we discovered the allegation was clearly malicious.
"The pupil who made the allegation was reprimanded by police.
"These are cases we see all to often and they are clearly distressing for teachers.
"We see this as a positive development and some sort of retribution for the pain and anguish suffered by the teacher."
She added: "This sets a precedent. I spoke to officers in our legal department and they couldn't find any record of it happening anywhere else.
"This was a huge step."
A North Wales Police spokeswoman said the pupil was not cautioned formally but received a reprimand.
A Flintshire Council spokesman said: "We are not aware of any incident of this nature in a Flintshire school."