The admission of misconduct by Glasgow Academy's headteacher has raised questions about whether the General Teaching Council for Scotland should have more powers over independent schools.
Peter Brodie had initially denied allegations of interviewing a 10-year- old boy in an "unprofessional and inappropriate manner" but, in a surprise move on Monday, he admitted the charge to the GTCS disciplinary sub- committee.
He was given a reprimand, to be removed from his record after five years.
The sub-committee could have taken the more severe action of striking him off the teaching register. In practice, however, this might have been no more punitive than a reprimand: while removal from the register prevents a state school teacher returning to his or her workplace, the GTCS has no such authority over the independent sector.
The sub-committee had heard from Mr Brodie's lawyer, Tim Glover, that he "valued his membership" and was keen not to lose it, despite having no obligation to register with the GTCS.
Another staff member involved in interviewing the boy about rumours of drug possession - school governors later agreed the boy was innocent - was never at risk of any action because he was not a GTCS member.
While GTCS registration is a requirement in the state sector, the Scottish Council of Independent Schools records that 86 per cent of teachers in its member schools are registered. It believes the actual figure is higher and is pushing for the vast majority to join, although it does not back mandatory membership.
This was described in a GTCS consultation document as opening up a "considerable loophole"; the council is striving to increase registrations in independent schools, although the Scottish Government has no plans to make it compulsory.
Mr Brodie admitted removing the 10-year-old boy from class for more than three hours on August 29 last year. He also accepted having interrogated the pupil for about one hour and 45 minutes, including a 15-minute break, without allowing him to be represented and supported by a responsible adult.
The sub-committee decided removal from the register would have been "disproportionate", even though GTCS solicitor Robbie Burnett had decried Mr Brodie's "remarkable lack of judgment" and the "reprehensible" decision to put the boy through a psychologically-damaging experience.
Conditional registration was also ruled out - such a sanction could have been more problematic than in the state sector since, as headteacher, the authority monitoring the conditions would have been Mr Brodie himself.
The only other options were to take no action, or issue a reprimand. The latter was deemed appropriate given the "distress" Mr Brodie had caused the boy, who now attends another school. There was also a "strong recommendation" that he go on a course to improve his techniques for interviewing children.
The sub-committee was "impressed", however, by Mr Brodie's admission of the charge, since this meant the boy - who followed proceedings with his parents from elsewhere in the GTCS Edinburgh headquarters - would not have to give evidence. It recognised that no evidence of "continuing psychological damage" had been presented.
It also took into account Mr Brodie's "contrition, and the dignity with which he conducted himself in the course of the hearing".
Mr Glover, however, took issue with GTCS solicitor Robbie Burnett's contention that the interview should have lasted five minutes at most. He said headteachers had "every right to investigate matters of discipline" and that an interview of up to 20 minutes before contacting parents would have been reasonable.
The boys' parents said the decision showed independent schools could not take the law into their own hands, and that justice had been done. They were unconvinced by Mr Brodie's claim that he was pleading guilty - which ended proceedings after two hours rather than the scheduled two days - to spare their son from giving evidence, since his decision was made "astonishingly late in the day".