It is a newly qualified teacher's worst nightmare. A pupil out of control, overturning chairs, stopping only to tell the helpless NQT to "fuck off".
What is there to do but call for help? Yet a member of the school's senior management team takes 20 minutes to arrive.
That was the experience of a 24-year-old woman during her first two terms teaching at a Hampshire secondary.
It is one of a number of stories unearthed by teaching unionNASUWT in a survey of 75 NQTs published this week.
The anonymous survey of teachers across the UK paints a picture of NQTs who are out of their depth, and ill-equipped to cope with bad behaviour.
Two out of five of those questioned said they had to deal with behavioural issues on an hourly basis, with 80 per cent saying discipline problems emerged daily and only 7 per cent describing them as rare.
One teacher had suffered three breakdowns due to physical and emotional exhaustion.
Persistent verbal aggression was reported by two-thirds of NQTs, 60 per cent had experienced persistent low-level indiscipline and 16 per cent occasional physical violence.
A 23-year-old primary teacher in Northern Ireland described how a pupil threatened to kick her before having a tantrum and being carried kicking and screaming from class by the principal.
Another primary teacher reported a full-scale fist fight between pupils in her class while a secondary science teacher from Stockport had a diary thrown at her head by a disgruntled pupil who then tried to escape through the classroom window.
Most of those questioned were two terms into their first teaching job.
The report said: "Incidents are not isolated to particular local authorities or types of schools but affect all schools regardless of level, sector or location."
Several teachers were already considering quitting state schools for the private sector, while others reported poor behaviour had damaged their health.
One described teaching as "25 per cent teaching, 75 per cent crowd control".
Another said: "After wanting to be a teacher all my life I now feel that I am not paid enough or respected enough by the Government to put up with this type of behaviour."
Only 14 per cent of NQTs said that their initial teacher training had done well in preparing them to manage behaviour in schools. This compared to 45 per cent who described it as adequate and 41 per cent who said that they had been poorly prepared.
They were more positive about the support they received from schools.
Two-thirds said they had received extra training and 87 per cent said the support they received was at least adequate.
Chris Keates, NASUWT general secretary, said: "This survey shows how important the Government's national initiative on behaviour is. This information will need to form part of the deliberations."
Professor Teg Wragg, education expert for Channel 4's Unteachables and a former teacher trainer, said: "There is no quick fix. Every new generation of teachers has to experience these problems for themselves. Even experienced teachers can struggle to deal with the toughest children."
Ready to face the worst?
What NQTs want from their training:
* more observations of classes with teachers who are particularly good at managing bad behaviour.
* greater use of role plays to help trainees act assertively and deal with real situations.
* better teaching of step-by-step strategies to deal with bad behaviour and a discussion of different options for different situations.