Jeremy Garrett, a science teacher at a middle school in the Bronx in New York, told his colleague David* not to worry about an allegation by a pupil. "One of the girls said he was looking at her ass," he says. "He was completely shocked and denied it all, and I told him that it would blow over. But the next day he was taken out of school and assigned to a rubber room."
In the UK, false allegations by pupils have an enormous impact on a teacher's career from the moment the claim is made - and even if the teacher is subsequently cleared. But in New York, claims of misconduct or even incompetence can result in teachers being sent to a temporary reassignment centre, also known as "rubber rooms", sometimes for years at a time, while they await a disciplinary hearing and a chance to defend themselves against the charge.
It is only in recent years, as teachers have started to campaign against the rooms, that awareness of them has become widespread.
Mr Garrett became aware of their existence when his colleague disappeared to one for six months. Yet there are an estimated 550 to 800 teachers in New York's seven rubber rooms.
This is, of course a tiny fraction of the 80,000 teachers in New York, but they form a determined group now fighting against what they see as the injustice of a system that takes experienced teachers out of schools for extended periods, at a time when there is a chronic shortage.
Many inhabitants of the rubber rooms have to wait for months before they can find out precisely what they are being charged with. Some teachers are even taken out of the classroom for an incident in their personal lives. A charge of drink driving, for example, is enough for a teacher to be sent to a reassignment centre.
The centres are nicknamed "rubber rooms" after the padded cells in psychiatric hospitals, and some teachers believe they are designed as hostile environments to encourage teachers to resign. They must be there for the whole school day, clocking in and out. They can spend their time doing as they please - writing, painting, doing yoga or perhaps playing Scrabble but are supervised by security staff.
"Each room develops its own kind of culture," says Mr Garrett, who is making a documentary on the subject to be released this year. "I've seen rooms where the teachers have free rein - they're playing checkers and chess, watching movies.
"Years ago, when we first started making the documentary and before they cracked down, people would bring in inflatable beds and sleep in there; they'd do night shifts and just sleep all day."
Rubber rooms were brought in by the New York Department of Education in the late 1990s as a way of dealing with teachers who it believes shouldn't be in the classroom.
Teaching union the United Federation of Teachers, which represents the bulk of teachers in New York City schools, negotiated a robust contract for tenured teachers with more than three years' experience, making it almost impossible to fire them. The education department gets around this problem by taking teachers out of the classroom, but continues to pay them in full.
However, the cost of paying people to do nothing is enormous. The average teacher salary in New York is equivalent to pound;43,600, with more experienced staff earning up to pound;61,400. The rubber room system for detaining teachers is thought to cost $53 million (almost pound;33 million) a year at the very least. The time teachers spend in the rooms is also drawn out because court hearings take place just five days a month, and only two days a month during summer holidays.
Education department spokeswoman Anne Forte says it has no choice. "When a teacher is accused of wrongdoing, we feel it necessary to remove the teacher," she says. "We have to weigh up the protection of the teacher's contract against the protection of the children. Even if the charge is severe, we can't get rid of them (the teachers)."
At the other end of the spectrum are charges of incompetence, yet teachers are treated in the same way and sent to the rubber room. "Even if it's a charge of incompetence, presumably the teacher isn't getting their job done," argues Ms Forte. "It's not a physical threat, but it's still a threat to the kids in terms of their education."
Art teacher David Pakter was assigned to a rubber room in 2004 despite being named "Teacher of the Year" by the then mayor, Rudolph Giuliani, in 1997. He was charged with subordination when he refused to hand over a video showing pupils from another school being taught music in his building while music provision for pupils attending his own school had been denied.
The charges were thrown out and he began working as a supply teacher. But two years ago, he was again sent to a rubber room in Harlem after giving watches he had designed to top-grade students. The gift was deemed to amount to promotion of a private business.
Mr Pakter and five other teachers have brought a class action against the education department for "unlawful confinement in teacher reassignment centres"; the case is ongoing.
Dr Joy Hochstadt, the lawyer representing them, says rubber rooms are being used by heads to get rid of whistle-blowers.
"Again and again, I see these nonsensical specifications in 3020-a charges (also known as Teacher Tenure Hearings, similar to a General Teaching Council hearing in England and Wales). Never have I seen it where a teacher taught substantively incorrect concepts, facts and ideas," she says.
Dr Hochstadt, a former teacher who spent time in the rubber room but was subsequently cleared of the charges against her, cites the case of Brandi Scheiner, a primary teacher for 24 years. She was sent to a reassignment centre for seating her pupils in the wrong way on the floor during story time and acceeding to a request from a five-year-old pupil for more glue.
"Mrs Scheiner is loud, funny, round and cuddly, the perfect type of kindergarten teacher and surrogate caretaker for students," she says. "These criticisms were not against her teaching: they were against Mrs Scheiner personally and against her top-scale salary."
US campaign groups such as Teachers 4 Action and the National Association for the Prevention of Teacher Abuse claim that the rubber rooms provide a route for heads to get rid of high-salary teachers. They claim that the Department of Education hopes that teachers will get so fed up with the rubber rooms that they resign, allowing the school to save on their salary.
Being paid to do nothing, even during school holidays, might seem an ideal scenario for some. But the vast majority of teachers consigned to the reassignment centres are not happy to be there.
Jennifer Saunders, a media teacher and former lecturer at New Jersey's Rutgers University, spent three years in a rubber room on 7th Avenue in Manhattan. "The atmosphere (in the room) was one that to me was dangerous," she says. "Anxiety was high because you were surrounded by people who you did not know, some of whom wouldn't talk."
In the time she was there, the number of teachers in the rubber room - most of whom were aged over 40 - increased from about 30 to 80. Brooklyn's Chapel Street reassignment centre is said to contain up to 300 teachers at a time.
"The room was so overcrowded that teachers were spilling out and sitting in the hallways and the vestibules," she says.
"It looked like a doctor's waiting room, with tables and chairs around the wall. People would work on their laptop, read a book, watch TV, or read the newspaper. You had some teachers who wanted to talk, and then other teachers who would be in and out of the room all day."
Anti-social behaviour in the rooms is a result of the emotional strain of the situation, says Mr Garrett. "Some people don't deal well with unstructured time and as a result they lash out. I've heard of fights breaking out, arguments, people breaking other people's things or stealing their coats," he says.
"These are really petty things, which in a normal work environment you wouldn't see. But because of the psychological effect that's underlying everything the regulations of everyday etiquette break down too."
As well as dealing with the stress of enforced confinement over long periods, teachers in the rubber room also have to put up with poor conditions. Mr Pakter describes his room as having "no available drinking water, no natural light, no plants and poor ventilation". The room in Manhattan was closed, says Mrs Saunders, because it violated health and safety regulations.
Dr Hochstadt also claims that the Public Employees Safety and Health Agency decided that poor air circulation in the room violated its code and resulted in health problems such as bronchitis, hypertension and other respiratory ailments.
One teacher, Gilda Teel, died of bronchial pneumonia in 2008, having been consigned to a rubber room since the previous year. Campaign groups blamed "these windowless, overcrowded disease-ridden rooms" for her deteriorating health.
Rubber rooms in New York exist against the wider backdrop of the commitment by mayor Michael Bloomberg to ridding the city's schools of incompetent teachers.
Just as in England and Wales, where a five-year MOT for teachers has been proposed, the accountability of teachers has become a major political issue. Fast-track schemes to recruit teachers have been introduced in New York, the model for Teach First in England, while experienced teachers are being removed from the classroom at any hint of a problem.
"We have emphasised the need to report all instances of misconduct to the special commissioner," says the education department's Ms Forte.
The department has introduced a "peer intervention programme" designed to provide mentoring and professional development to struggling teachers. But some staff still claim that the rubber room system is being abused by heads.
"A lot of the people who arrive there have done nothing wrong, so it shouldn't be a question of having to discipline them," concludes Mr Garrett.
Does the mayor have too much control?
Until 2002, charges against New York teachers would be dealt with by the borough's education committee. If the board decided the case should go to court, teachers would be sent to a rubber room until the hearing. But in 2002, Mayor Bloomberg replaced the local committees with a panel for educational policy; eight of the 13 members are his appointees.
Changes to the education system have led critics to complain that the mayor and Joel Klein, chancellor for NYC schools, have too much control over education. But with improved standardised test scores and graduation rates now on the up, the Senate voted last summer to retain almost complete mayoral control of the city's school system for another six years.