Parents and pupils voiced their dissatisfaction with the leadership of Jonathan Miller as news of his resignation as JFS head teacher was announced this week.
Some parents said they had been worried that a number of staff had left to be replaced by a "string of supply teachers brought in to fill the gaps."
One parent who wished to remain anonymous said: "Several teachers left and they were not replaced properly."
Others complained that the marking of students' work was often "inconsistent" and of "poor quality".
The lack of trips provided for pupils in years seven and eight was also criticised, with some claiming that it caused "serious frustration".
Hall monitors would demand you show them your pass
Another parent said she was concerned about the school's approach to discipline.
She added that Mr Miller had suspended six pupils around the time of the critical Ofsted report that downgraded the school from "outstanding" to one requiring improvement, and claimed that the head's departure was "about poor performance".
Another parent said that "detentions were given out like confetti".
Teachers appeared to have been given a quota to fulfil and handed out detentions to pupils "for no apparent reason", he claimed.
The JC understands that last week the school suspended a male pupil for two weeks after he was "caught smoking drugs on school grounds".
A former pupil who attended JFS between 2000 and 2007 said that the culture of the school changed dramatically after Mr Miller took over as head.
She said: "It was not to the taste of students. Hall monitors were brought in - not qualified teachers. They would traipse up and down the corridors looking at the length of skirts.
"If you were out of class on the way to the toilet for example, they would run after you and demand a hall pass - something that was not in place prior to that."
Mr Miller continued to have a special venue for detentions known as "Room 17" after its introduction by his predecessor Dame Ruth Robins.
Former students remember repeatedly being sent to the room, where a rule of absolute silence was enforced, with one teacher in charge.
One mother, who said her child was largely happy with the school, nonetheless complained that "discipline had been too heavy handed recently."
She said there was a "zero tolerance policy on uniform that is ridiculously harsh" and said the tone at school meetings was often "impersonal and a lot of PR."
However, Richard Simmons, who was head boy in 2005 when Mr Miller was a science teacher, said he was "saddened" to hear of his resignation..
Mr Simmons said: "He was one of the most fantastic teachers I had and I look back on his lessons fondly.
"He is a man who inspired his students, gave them an excellent work ethic and wanted every student to reach their full potential and shine.
"He was a true leader who led from the front and worked tirelessly for the school in his 30 years of dedication."
