An assistant headteacher who used his mobile phone to film up schoolgirls' skirts will not face prosecution after a judge ruled his actions were not illegal.
Andrew Corish, 60, took photographs and videos while at Coloma Convent Girls' School in Croydon, south London.
He faces a teaching ban after admitting to a professional misconduct panel he had taken and kept the images for his sexual gratification.
But he will not face criminal proceedings because his actions did not break the law.
A National College for Teaching and Leadership (NCLT) disciplinary panel last week heard Mr Corish, from Caterham, Surrey, admitted using his phone “to film up the skirt of one or more pupils”.
He stored “one or more inappropriate images taken up the skirts of pupils, including videos”, the panel heard.
It found he "breached teachers' standards" and it is expected to recommend sanctions, possibly including a classroom ban, to the Department for Education later this month.
Mr Corish was suspended by the school - one of the country's top-performing comprehensives - after allegations against him emerged in 2015. He subsequently resigned from his position.
He was arrested and charged with voyeurism, and pleaded guilty at Croydon Magistrates' Court in April last year.
But at a sentencing hearing at Croydon Crown Court the following month, Judge Warwick McKinnon ruled the charge did not correctly apply to the teacher's alleged offence and set aside his guilty plea.
Voyeurism is defined by the Sexual Offences Act 2003 as "observing another person doing a private act" without consent "for the purpose of sexual gratification".
Judge McKinnon ruled none of Mr Corish's alleged victims "were involved in a private act under the legal definition," said a Crown Prosecution Service (CPS) spokesman.
The spokesman added: “The prosecution did try to add charges of making indecent images of a child. However, the judge viewed the images and determined that they were not of an indecent nature, meaning this charge could not be pursued.
“As a result, the CPS offered no evidence.”
A spokeswoman for Coloma Convent Girls' School said it "thoroughly condemned this former teacher's behaviour".
The school assisted the police investigation, reported Mr Corish to the NCTL and has "reviewed and further strengthened our safeguarding procedures," she added.
Last month Justice Secretary David Lidington said the government was considering making "upskirting" a criminal offence.
He said he was taking the issue "very seriously" and had asked for legal advice in response to a petition, signed by more than 70,000 people, calling for changes to legislation.
The petition was started by Gina Martin after a man took a photo up her skirt without her knowledge at a music festival in London's Hyde Park.
She reported the incident to police but was told they could do nothing as the man had not broken the law.