Students texting, chatting, surfing the net, and swearing - these are just some of the challenges that further education lecturers face in today's classrooms.
Most teachers quickly develop strategies to deal with such disruption.
Faced with students talking continually, attention-seeking and distracting other learners, they set ground rules, switch to new activities and, above all, try to keep calm.
But trainees and new lecturers often find it tough, and feel uncertain about whether they should tackle such behaviour or ignore it and hope it goes away.
Ros Clow, leader of the part-time postgraduate teacher-training course at Oxford Brookes University, says it is essential to differentiate between disruptive behaviour and "annoyances" such as chatting in class or failing to hand in work on time.
"Disruptive students create chaos in what should be a learning environment," she says. "Managing them is something that worries trainee teachers and qualified teachers alike - often out of all proportion.
"I have been teaching for 20 years, and I don't think there are more disruptive students in colleges now than before.
"It is always a minority of students who disrupt - never the whole group.
In post-16 education difficult behaviour usually comes from younger students, and it tends to be in theory-based classes in which learners don't like sitting still for long periods."
But Claire George, 14-19 Pathfinder manager at Boston college in Lincolnshire, resents the assumption that younger students are more disruptive. She says that the 632 14 to 16-year-old students at Boston college behave "beautifully".
"We have found that 14 to 16-year-olds do not run riot," she says. "Most here are mainstream key stage 4 students who spend a day a week doing a vocational course.
"The idea that 14 to 16-year-olds don't behave in classes irritates me - because they can and do."
Boston has put a lot of time and effort into managing the learning environment and helping staff with classroom skills.
Ms George adds: "You have to take on board the needs of young learners and accommodate the fact that their literacy skills are at a lower level, and their attention spans are sometimes shorter.
"We have found no more behaviour problems with our14 to 16 group than in our full-time cohort - they are not a marauding crew."
There's no doubt, however, that the students who disrupt classes in FE colleges do so for a many reasons - ranging from negative experiences of school to difficulties in learning.
"If someone is struggling, then they will often disrupt a lesson as a way of disguising their difficulties," says Ms Clow.
"They may do it to avoid working, or being shown up. Perhaps they don't want to be in the classroom at all.
"It's not always the lower-ability students, either. High-ability students sometimes disrupt classes because they are bored. And, of course, with young students a lot of it is hormonal."
Ms Clow's advice to her trainee teachers is to ensure that they get good peer and mentor support from the outset.
"There isn't a magic button that you can press to solve behaviour problems," she says. "Teachers need a good tool kit of ideas to try - strategies such as mixing up students, putting them into groups and separating friends. These are all highly effective."
Researchers have found that most FE colleges have clear policies and procedures to tackle disruptive behaviour. But as far back as 1998, the "Ain't Misbehavin'" report, published by the then Further Education Development Agency (now the Learning and Skills Development Agency), warned that the issue was "likely to increase rather than decrease" in post-16 education.
Dan Taubman, national education official for the lecturers' union Natfhe, says disruptive behaviour is generally dealt with effectively by colleges.
"We do not give advice on behaviour management per se," he says. "There should be college procedures in place. We ask people what staff development and support they are receiving - but if that isn't forthcoming and they are not getting anywhere we would take it up."
Earlier this year, the LSDA published a survey which examined how effective FE lecturers had found their initial teacher training in equipping them for life in the classroom.
The research, led by Ros Clow and Joe Harkin of Oxford Brookes and Yvonne Hillier of City University in London, found that 90 per cent of lecturers regarded their training as "helpful" or "very helpful".
But they did want more advice on class management and dealing with disruptive students.
Debbie Smith, a new computer studies teacher, has had to deal with students texting and surfing the internet during her lessons.
"Individually, they are all nice but they get a bit laddish in a group. The trouble is that I don't know what tutors could do to prepare us for disruptions like that. It's a life experience that you just have to go through."
Psychology lecturer Sarah Allen gained her PGCE in post-compulsory education this summer and began her first full-time FE teaching post in September. Up to now she has encountered few serious problems, although she has had to contend with students chatting, swearing and, in one case, a student playing with a skateboard in the classroom.
While she was training a drunken student got up and walked out of her lesson. She dealt with this by arranging a meeting with him and his personal tutor the following week to discuss his behaviour.
"On the whole I tend to cope with problems by tackling them head-on," she says. "Or students think they can get away with it.
"I'm a great believer in giving responsibility to students, and making them think about the consequences of their actions. I tell them it is their own time they are wasting."