Pupils who make false allegations against teachers should be expelled with immediate effect. It happened to me when I was teaching, and the lying pupils weren't even made to apologise. They can destroy a perfectly innocent person's career, robbing them of an income and a livelihood. Fortunately, in my case, they were found out, but there were zero consequences.
Permanent exclusion with no right of appeal and no compulsion for any other school to accept such an excluded student.
And no grief for the heads who exclude them, either, nor any `second chance' nonsense.
Any investigation into allegations against a teacher should start from the premise that teachers are innocent until proven guilty; and that a teacher who is under investigation for any sort of allegation should not be named in the media until or unless she or he is found guilty.
Once a malicious allegation has been proved, a `caution' status should be placed against the pupil's UPN (unique pupil number). There should be an automatic charge of `wasting police time' against the pupil andor the pupil's parents if police have been involved. Compensation should be paid to the teacher by the pupil's parents according to a nationally recognised scale, enforcible in law.