Parents at a Stroud grammar have launched a campaign to reinstate their dismissed head.
Roger Lock was fired from Marling School earlier this term, following a two-day hearing by the board of governors. He had been suspended six months earlier.
The exact nature of the allegations against him remain unknown, but they do not involve pupils. It is understood that union representatives and governors have questioned staff to determine whether there was evidence of bullying and harassment.
Marling parents have since formed a protest group in defence of Mr Lock, distributing leaflets outside the school gates earlier this week in the company of several inflatable kangaroos - a reference to their belief that he was judged by a kangaroo court.
A 2007 Ofsted report raised concerns about "inadequate" governance at Marling and a new chair of governors was installed last year. The inspectors rated the school's leadership as satisfactory and said that teaching and learning were occasionally good or outstanding.
Mr Lock's case has been taken up by David Drew, MP for Stroud, who raised it in the House of Commons.
He said: "I am sad because the case has done enormous damage to the school by setting people against one another."
He added that Mr Lock was not allowed to watch his son play rugby for Marling because he has been barred from school premises.
Mr Lock, who had worked at Marling for 30 years before his dismissal, is expected to appeal against the decision. ab.