A male teacher's sexual relationship with a female student was only uncovered after her mother found more than 400 text messages between the pair.
The teacher, Ewen Mason, who taught at an unnamed New Zealand school, admitted having a sexual relationship with the then Year 13 student which started with text messages late at night and early in the morning.
He has been censured and had his registration cancelled following an Education Council's Complaints Assessment Committee investigation and hearing which called the sexual relationship "reprehensible".
The student has now left school and the pair are still in a relationship.
The decision prohibits the publication of the girl's name, the school and region where it happened, what subjects the teacher taught and how their association started.
However, the relationship with 'student X' started in 2015, a year after the teacher started working at the school.
He'd previously taught at primary and secondary schools as well as in the UK since 2000.
They started sending text messages to each other at both ends of the day.
"At some stage the relationship became sexual," the decision reads.
The decision also says Mr Mason counselled the girl when he had no adequate experience.
The council says the counselling indicated the student "had particular vulnerabilities" before they started the relationship and there was evidence of "actual harm" to her.
In August 2015, the girl's mother discovered charges for 472 messages and four phone calls between the pair on her bill.
When she was confronted, the girl said the couple were in a relationship.
Mr Mason resigned from the school the following day with immediate effect and while the principal was contacting him about the resignation, the parents raised the inappropriate relationship.
The decision says Mr Mason cooperated with the investigation and admitted what he'd done was wrong and being struck off was an appropriate response.