Derek Ross, former principal teacher of drama at Elgin Academy, will not be reinstated after a tribunal ruled he was 80 per cent to blame for his dismissal.
But Moray Council is likely to appeal against the tribunal's finding that Mr Ross was unfairly dismissed and an award of Pounds 1,549. It is defending the actions of Norman Strachan, Elgin Academy's headteacher, said by the tribunal to have mishandled the incident.
Mr Ross, aged 42, allowed a group of 15 to 17-year-olds to drink excessively on a school outing to a theatre in Dundee. One pupil was sick over the back of a pupil from another school during the performance. He was dismissed by the council last February following a hearing before the education committee but challenged the decision at an industrial tribunal.
The tribunal accepted he was unfairly dismissed but stressed the council did not act "unreasonably". Mr Ross had admitted culpability but it states that much of his evidence was "designed to muddy the waters and divert attention into a labyrinth of side issues".
The General Teaching Council refused to strike Mr Ross from the register and he has been working as a supply teacher in Aberdeen.
In a written judgment, the tribunal found Moray had conducted a full and fair hearing, although its verdict was considered harsh by one tribunal member. The tribunal believes Mr Strachan should have dealt with the case differently, perhaps by giving an initial warning and not taking the matter to his superiors immediately.
Mr Strachan did not follow procedures as he might have, according to the judgment. The authority, however, is likely to challenge that assessment at an appeals tribunal. The head was only following council guidelines, it contends.
The Educational Institute of Scotland, Mr Ross's union, suggested it was normal practice for the union to agree with the employer alternatives to dismissal such as early retirement, transfer to another school or demotion. None of these were discussed. The council's education committee was wrongly advised that demotion was not an option.
The tribunal states it would not be appropriate to reinstate or re-engage Mr Ross after he accepted his misconduct.
Margo Howe, the council's education convener, said: "While concerned with regard to the minor procedural issue raised in the course of the tribunal, Moray Council is pleased that its stance in this case has been vindicated. "